t     < 


LIBRARY 

OF  THF. 

University  of  California. 

EDUC. 

PSYCH. 

LIBRARY 

«l 


GENETIC    PSYCHOLOGY 


THE  MACMILLAN  COMPANY 

NEW  YORK    •    BOSTON   •    CHICAGO 
ATLANTA   •    SAN   FRANCISCO 

MACMILLAN  &  CO.,  Limited 

LONDON   •    BOMBAY   •    CALCUTTA 
MELBOURNE 

THE  MACMILLAN  CO.  OF  CANADA,  Ltd. 

TORONTO 


GENETIC   PSYCHOLOGY 

AN    INTRODUCTION 

TO    AN 

OBJECTIVE  AND  GENETIC  VIEW 
OF    INTELLIGENCE 


BY 

EDWIN   A.    KIRKPATRICK,  B.S.,  M.Ph. 

AUTHOR   OF   "  FUNDAMENTALS   OF   CHILD    STUDY  " 


THE   MACMILLAN   COMPANY 
1910 

All  rights  reserved 


10L06 


± 


EDUC. 

PSYCH. 

LIBRARY 


Copyright,    1909, 
By  the    MACMILLAN    COMPANY. 


Set  up  and  elcctrotyped.     Published  May,  1909.     Reprinted 
January,  1910. 


Nortoooli  ilreaa 

J.  S.  Gushing  Co.  —  Berwick  &  Smith  Co. 

Norwood,  Mass.,  U.S.A. 


PREFACE 

The  theory  of  evolution  has  completely  revolu- 
tionized the  biological  sciences  and  is  now  mak- 
ing similar  changes  in  psychology,  the  science 
dealing  with  the  highest  form  of  life,  that  of  con- 
sciousness. All  life  phenomena,  from  those  of 
plant  growth  to  the  most  complex  processes  of 
consciousness,  are  in  certain  respects  similar. 
Therefore,  not  until  the  facts  and  theories  of  all 
sciences  concerned  with  life  phenomena  have  been 
studied  to  determine  their  common  and  their  dif- 
ferentiating characteristics,  can  we  have  a  psy- 
chology that  is  a  fitting  apex  of  these  sciences. 
In  other  words,  all  psychology  must  be  founded 
on  genetic  principle;^  and  become  genetic  in 
character. 

It  is  with  the  purpose  of  helping  to  more  clearly 
define  and  establish  this  point  of  view,  which  is 
being  more  and  more  taken  by  present-day  stu- 
dents of  life  activities,  that  this  book  has  been 
prepared.  It  is  hoped  that  this  tentative  formu- 
lation of  the  truths  supplied  by  various  sciences 
may  help  to  promote  more  harmony  of  effort  on 
the  part  of  workers  in  the  several  related  fields. 


vi  PREFACE 

In  origin  and  plan  of  treatment,  however,  peda- 
gogical interest  has  played  a  large  part.  After 
nearly  a  score  of  years  devoted  to  the  study  of 
child  psychology,  the  impulse  to  formulate  the 
broader  truths  of  genetic  psychology  as  a  dis- 
tinct subject  came  from  the  experience  of  giving 
courses  in  both  subjects  to  summer  students  at 
Columbia  and  Chicago  Universities.  The  inter- 
est and  comprehension  shown  by  those  students 
developed  the  belief  that  the  facts  of  genetic  psy- 
chology, incomplete  as  they  are,  could  be  profitably 
formulated  for  the  use  of  educators.  Subsequent 
experience  in  giving  parts  of  this  book  in  nearly 
their  present  form,  to  a  class  in  a  normal  school, 
has  confirmed  this  belief.  It  is  probable  also  that 
popular  interest  is  great  enough  to  make  the  book 
acceptable  to  the  more  serious  of  those  interested 
in  animal  behavior.  Teachers  will  be  most  inter- 
ested in  Chapters  IX  and  X,  treating  of  various 
types  of  intelligence. 

In  working  out  the  general  principles  of  mental 
genesis  it  was  found  that  the  more  specific  problem 
of  mental  phenomena  as  organized  in  individual 
minds  could  not  be  satisfactorily  treated  till  the 
general  truths  of  organic  activity  and  of  mental 
genesis  had  been  formulated,  and  that  space 
would  not  admit  of  the  treatment  of  both  in 
a  single  volume.  The  author  hopes  to  treat 
of  mental  development  in  individuals  and  some 


PREFACE  vii 

of  the  pedagogical  implications  in  a  subsequent 
volume. 

The  author  is  indebted  to  so  many  patient  in- 
vestigators and  writers  for  facts  and  suggestions 
that  no  enumeration  other  than  is  indicated  by 
the  references  will  be  made.  To  Dr.  Jennings 
he  is  also  much  indebted  for  the  use  of  a  number 
of  cuts.  For  stimulus  to  the  work  the  author  is 
most  indebted  to  students,  and  for  literary  help 
to  his  wife.  Acknowledgment  is  also  gratefully 
made  to  Dr.  C.  F.  Hodge  for  suggestions  con- 
cerning Chapters  II  and  VI  and  to  Dr.  A.  H. 
Pierce  for  criticisms,  especially  concerning  con- 
sciousness, although  neither  is  responsible  for 
anything  the  book  contains. 

E.  A.  K. 

FiTCHBURG,  January,  1909. 


LITERATURE 

The  books  most  likely  to  be  helpful  to  students 
of  this  work  are  the  psychologies  of  James,  Angell, 
Thorndike,  and  Judd,  and  the  following  books: 
Morgan's  "  Comparative  Psychology,"  Hobhouse's 
"  Mind  in  Evolution,"  Washburn's  "  The  Animal 
Mind,"  and  some  such  zoology  as  Jordan  and 
Kellogg's,  References  to  these  and  considerable 
other  literature  will  be  found  at  the  close  of  each 
chapter,  but  no  attempt  has  been  made  to  con- 
struct a  complete  bibliography.  References  likely 
to  be  most  generally  useful  and  accessible  to  stu- 
dents are  starred. 


CONTENTS 


PAGE 

Preface         .        .        .        .      • v 


Literature 


CHAPTER   I 

Introduction 

Nature  and  Scope i 

General  Characteristics  of  Organisms       .....         5 

Evolution  and  the  Genesis  of  Behavior  and  of  Mind        .         .         8 
The  Psychic  Factor  in  Behavior      .         .         .         .         .         .13 

References       .         .         .         .         .         •         .         .         .         .14 

CHAPTER   II 

Structural  Basis  of  Behavior 


General  Principles  ..... 

Specialization  of  Sensitive  Structures 

Suggestive  Stimuli  .... 

Somatic  and  Kinsesthetic  Sense  Structures 

Development  of  Motor  Structures    . 

Somatic  Motor  Apparatus 

Specialization  of  Connecting  and  Regulating  Apparatus 

References  


16 

17 
26 

30 
31 
33 
33 
37 


CHAPTER   III 

Types  of  Animal  Behavior 

Amoeba  ...........  39 

Infusoria  —  Paramecium  ........  43 

Lower  Forms  of  Metazoa  —  Mydra,  Medusa     ....  53 

Starfish   ...........  58 


xu 


CONTENTS 


PAGB 

Mollusca 60 

Crustacea        ..........  62 

Fishes 64 

Amphibia        ..........  66 

Frogs 66 

Tortoises 67 

Insects 68 

Ranatra    ..........  68 

Ants         ..........  72 

Mammals  and  Birds 76 

Guinea  Pigs 76 

White  Rats 78 

Domestic  Animals  and  Birds 81 

Raccoons  and  Monkeys    .......  83 

Summary  of  Characteristics  of  Behavior           ....  85 

DiiTerentiation  of  Physiological  Processes  and  Behavior  .         .  87 

References 88 

CHAPTER   IV 


Imitation,  Curiosity 


Complex  Behavior  Characteristic  of  Species  — 
Instincts 

Nature  and  Differentiation  of  Instincts    . 
Fundamental  Forms  of  Instinctive  Behavior 

Individualistic  Instincts 

Parental  Instincts     . 

Social  Instincts 

Adaptive  Instincts,  Play, 
Specialization  of  Instincts 

Constructive  Instinct 

Collecting  Instinct 

Esthetic  Instinct 

Teasing   . 

Jealousy  . 

Expressive  Instinct 

Regulative  Instincts 
References 


92 
93 
93 
95 
97 

99 
102 
102 
102 
103 
105 
105 
106 
106 
109 


CONTENTS 


XUl 


CHAPTER  V 

Behavior  of  Individuals  —  Acquisition  of  Habits 
AND  Ideas 

PAGE 

Habit  Formation     .         .         . iii 

Complications  of  Instincts  and  Habits      .         .         .         .         .119 

Free  Ideas       •         .         .         .         .         .         .         .         .         .126 

References      .        .         .         .         .         .        .         .         .         '139 

CHAPTER    VI 

Structures  Concerned  in  Complex  Behavior  and 
IN  Ideation 

The  Nervous  Apparatus  of  Vertebrates 141 

Differences  between  tlie  Nervous  System  of  Man  and  of  Other 
Animals        .         .         .         .         .         .         .         .         .         .146 

General  View  of  Brain  Functioning  .         .         .         .         .152 

Physiological  Basis  of  Special  Mental  Processes       .         .         .156 
Perception        .         .         .         .         .         .         .         .         .156 

Mental  Images  .         .         .         .         .         .         .         .158 

Memory  Images        ........     160 

Concepts  .........     161 

Physiological  Mechanism  of  Attention  and  Thought        .         .     162 
References ;         .         .     168 

CHAPTER   VII 


Consciousness 

Objective  Tests  of  Intelligence  and  Criteria  of  Consciousness 
I.    Structure    . 
II.    Behavior    . 

1.  Discrimination 

2.  Motion 

3.  Purposefulness 

4.  Modifiability 
Subjective  Criteria  of  Consciousness  and  its  Functions 
Organic  Unity  and  Continuity  .... 


169 
169 
171 
171 
172 

174 
176 
179 
191 


XIV 


CONTENTS 


PAGE 

Seeming  Continuity  of  Consciousness      .....  193 

01)jective  and  Subjective  Terms       ......  198 

Probable    General    Characteristics   of    the    Consciousness   of 

Animals       ..........  206 

References 211 

CHAPTER   VIII 


Specific  Conscious  States 


General  Character  of  Feeling  in  Animals 
Pain        .... 
Intellectual  States   . 

Sensations 

Space  Perception 

Perception  of  Objects 

Images  and  Memories 

Concepts  and  Reasoning 
Volitional  Activity  . 
References 


214 
217 
222 

222 
227 

233 

238 
247 
250 
254 


CHAPTER   IX 


Types  of  Adaptive  Activity  or  Intelligence 

A  Broader  Conception  of  Intelligence 

Physiological  Intelligence 

Sensory  Motor  Intelligence 

Representative  Intelligence 

Conceptual  Intelligence  . 

The  Four  Types  of  Intelligence  in  Man 

References       ..... 


257 
259 

264 
270 
275 
281 
284 


CHAPTER  X 

Types  of  Learning  Activity 


Nature  of  Learning 

The  Physiological  Type  of  Learning 


286 
288 


GENETIC  PSYCHOLOGY 

CHAPTER  I 

INTRODUCTION 

NATURE  AND   SCOPE 

Psychology  is  usually  defined  as  "the  science  of  mind 
or  consciousness."  The  words  "Genetic  Psychology" 
therefore  at  once  suggest  a  science  concerned  with  the 
beginnings  and  growth  of  mind.  One  naturally  thinks  of 
it  as  dealing  with  the  growth  of  ideas  or  other  states  of 
consciousness  in  the  minds  of  adults,  of  the  development 
of  children's  minds  and  of  the  various  grades  of  animal  in- 
telligence and  its  development  from  the  lowest  species  of 
animals  to  the  highest  races  of  men.  These  ideas  sug- 
gested by  the  name  all  properly  belong  with  the  phe- 
nomena considered  in  this  new  science. 

Genetic  psychology  is  properly  concerned  with  changes 
in  minds,  especially  with  their  development  from  simple 
beginnings  into  more  complex  forms,  yet  in  order  to  know 
the  facts  regarding  such  changes  and  the  laws  of  develop- 
ment, we  cannot  limit  its  field  to  a  study  of  changes  as  they 
take  place.  Changes  involved  in  the  development  of  ideas 
and  of  minds  may  extend  over  periods  of  time  ranging  from 
minutes  to  millions  of  years.     The  same  mind  cannot  be 


2  GENETIC   PSYCHOLOGY 

studied  continuously  but  the  changes  must  be  observed  at 
intervals.  In  many  cases,  instead  of  comparing  the  same 
individual  at  different  ages  it  is  necessary  to  compare  indi- 
viduals of  different  ages  and  to  compare  species  with 
species.  In  the  study  of  the  genesis  of  mind  in  the  race  it 
is  utterly  impossible  to  observe  the  changes  as  they  take 
place,  and  the  only  mode  of  procedure  possible  is  to  study 
the  difference  in  the  minds  of  lower  and  higher  animals 
and  men,  with  a  view  to  determining  what  changes  have 
taken  place,  on  the  theory  that  simpler  forms  of  minds 
have  developed  into  more  complex  forms,  and  the  simpler 
feelings  and  ideas  into  those  of  a  higher  type. 

Comparative  psychology  is  primarily  concerned  with 
comparing  and  grading  the  intelligence  of  different  species 
of  animals  and  races  of  men,  but  genetic  psychology  is 
interested  in  grading  the  intelligence  of  animals  only  as  a 
means  of  knowing  what  changes  have  taken  place  in  the 
evolution  of  mind  in  the  race,  the  order  of  such  evolution, 
and  the  relation  to  each  other  of  different  types  of  mental 
activity. 

In  attempting  to  compare,  for  the  purpose  of  discovering 
changes  in  mind  and  ascertaining  the  laws  of  development, 
it  is  necessary  to  begin  with  characteristics  that  are  com- 
mon to  all  creatures,  rather  than  those  possessed  only  by 
the  higher  creatures. 

Common  characteristics  in  organisms  may  be  sought 
(i)  in  structure,  (2)  in  behavior,  and  (3)  in  conscious  states. 
In  ourselves  and  the  higher  animals  these  are  all  closely 
correlated,  and  it  is  reasonable  to  suppose  that  the  same  is 
true  of  the  lower  animals  in  so  far  as  they  possess  these 
three  characteristics.     There  is  no  doubt  that  all  organ- 


INTRODUCTION  3 

isms  are  similar  in  being  composed  of  protoplasm  and  that 
they  are  active.  Hence  structure  and  behavior  are  com- 
mon to  all.  The  third  characteristic,  that  of  conscious 
states,  cannot  be  directly  observed  in  animals,  but  can  only 
be  inferred  from  structure  and  behavior.  We  are  justified 
in  inferring  consciousness  only  when  their  behavior  has 
the  same  characteristics  as  behavior  in  ourselves  that  is 
always  accompanied  by  consciousness. 

It  is  clear  that  the  basis  of  genetic  psychology  should  be 
entirely  different  from  that  of  general  psychology.  The 
general  psychologist  finds  in  his  own  mind  a  great  variety 
of  mental  phenomena,  and  by  observing  the  actions  of 
others  and  listening  to  their  words,  he  can  compare  his 
mental  states  with  those  of  others  and  thus  determine  the 
general  truths  regarding  conscious  states  in  adult  human 
beings  and  the  general  laws  of  conscious  activity.  Physi- 
ological psychology  supplements  his  study  ,by  facts  of 
anatomy  and  physiology,  while  the  experimental  psy- 
chologist makes  exact  observations  and  measurements  of 
mental  states  and  objective  behavior  under  definitely  de- 
termined conditions. 

In  genetic  psychology  the  mode  of  procedure  must  be 
the  reverse  of  that  followed  by  the  general  psychologist. 
It  must  begin  with  structure  and  behavior  instead  of  with 
mental  states.  The  student  of  genetic  psychology  cannot 
observe  the  mental  states  of  animals  and  infants,  but  the 
structure  and  the  behavior  of  the  simpler  organisms  may 
be  studied  with  great  exactness  and  a  basis  thus  formed 
for  inference  regarding  probable  mental  states.  The 
comparative  simplicity  of  such  organisms  and  the  possi- 
bility of  removing  parts  without  destroying  life  is  of  great 


4  GENETIC   PSYCHOLOGY 

advantage  in  this  mode  of  procedure.  The  facts  regarding 
structure  and  behavior  of  all  creatures  from  the  lowest  to 
the  highest,  are  open  to  investigation  by  this  method,  while 
the  facts  of  consciousness  may  be  directly  studied  only  in 
one's  own  mind.  The  genetic  psychologist  cannot  obtain 
a  knowledge  of  the  mental  states  of  animals  and  young 
children  by  means  of  words  as  can  the  general  psychologist 
learn  of  the  mental  states  of  adults.  It  would  be  very 
unwise,  therefore,  for  the  genetic  psychologist  who  seeks 
to  trace  the  development  of  mind  in  the  race  from  the 
lowest  animals  to  man,  to  base  his  science  on  the  facts  of 
consciousness.  He  must  start  with  the  facts  of  structure 
and  behavior  and  trace  their  growth  in  complexity  in  the 
race  and  in  the  individual. 

In  order  that  he  may  not  unintentionally  base  his  science 
on  facts  regarding  conscious  states  that  are  possessed  by 
himself  but  that  perhaps  are  not  found  at  all  in  animals 
and  infants,  he  should  describe  the  facts  of  behavior  as  far 
as  possible  in  objective  terms.  When  the  facts  and  laws 
of  behavior  in  animals  and  children  have  been  determined 
without  reference  to  consciousness,  then  inferences  as  to 
whether  the  activities  described  were  or  were  not  accom- 
panied by  consciousness  may  be  made.  In  doing  this  the 
behavior  of  adult  human  beings  must  be  studied,  not  as  does 
the  general  psychologist  by  giving  the  chief  attention  to  the 
most  prominent  conscious  states,  but  to  the  least  prominent 
conscious  states  and  to  the  activities  that  may  be  carried 
on  successfully  with  little  or  no  consciousness.  Inferences 
regarding  conscious  states  of  animals  and  children  may 
best  be  made  from  the  states  that  are  the  least  prominent, 
least  highly  developed,  and  that  have  been  least  considered 


INTRODUCTION 


5 


by  the  general  psychologist,  since  the  mental  states  dis- 
covered by  the  finer  analysis  of  the  general  psychologist 
are  likely  to  lead  away  from  rather  than  toward  the  truth. 
The  genetic  psychologist,  therefore,  in  order  to  ac- 
complish his  purpose  of  throwing  light  on  the  genesis  of 
mental  states,  must  take  the  point  of  view  of  the  objective 
sciences,  and  must  determine  the  facts  regarding  activity, 
behavior,  functioning,  whether  conscious  or  unconscious, 
before  attempting  to  describe  the  development  of  conscious 
states.  There  must  first  be  the  science  of  the  genesis  of 
behavior  before  a  true  science  of  the  genesis  of  mind  and  of 
conscious  states  can  exist.  The  genetic  psychologist  must 
study  the  typical  modes  of  behavior  of  all  organisms,  even 
giving  some  attention  to  the  growth  activities  of  plants, 
the  laws  of  which  conform  to  the  fundamental  laws  gov- 
erning the  behavior  of  animals.  By  thus  determining  the 
fundamental  facts  and  laws  of  activity,  whether  conscious 
or  unconscious,  he  will  be  able  to  formulate  more  correctly 
the  laws  of  psychical  development  which  may  be  looked 
upon  as  one  form  of  activity. 

GENERAL   CHARACTERISTICS   OF   ORGANISMS 

Since  genetic  psychology  is  concerned  with  all  kinds  of 
organisms,  it  is  worth  while  to  spend  a  little  time  in  getting 
a  conception  of  the  essential  characteristics  of  an  organism. 

An  organism  may  very  well  be  regarded  as  a  living 
machine  composed  of  protoplasm,  built  in  nature's  factory, 
and  fitted  as  are  other  machines  for  doing  certain  things. 
A  machine  is  made  in  a  comparatively  short  time  and  does 
not  change  its  structure  except  in  the  way  of  wearing  out, 


6  GENETIC   PSYCHOLOGY 

decaying,  or  breaking.  An  inorganism  is  a  growth  from 
small  particles  of  other  organisms  whose  ancestors  have 
a  long  history  of  development,  and  it  is  changed  by  every- 
thing that  it  does  into  something  somewhat  different  from 
what  it  was. 

An  organism  differs  from  an  inorganic  machine  in  being 
self-running,  self-feeding,  self-repairing,  self-changing, 
self-regulating,  and  self-reproducing.  No  machine  or  in- 
organic substance  is  capable  of  doing  any  of  these  things 
to  any  considerable  extent.  These  characteristics  may 
all  be  expressed  in  a  sentence  by  saying  that  an  organism 
possesses  and  maintains  unity. 

A  crystal  has  unity  but  does  not  maintain  it.  If  a  crystal 
is  injured,  it  does  not  repair  the  damage ;  but  if  a  plant  or 
animal  is  injured,  not  too  seriously,  the  damage  is  repaired. 
A  molecule  has  unity  which  it  maintains  under  certain 
circumstances,  but  with  change  of  temperature  and  contact 
with  other  molecules,  the  unity  may  be  broken,  the  atoms 
enter  into  new  combinations  and  form  a  unity  of  an  entirely 
different  type.  In  an  organism,  on  the  other  hand,  though 
the  molecules  of  which  it  is  composed  are  continually  chang- 
ing, yet  the  unity  of  the  organism  is  maintained.  Indeed, 
change  in  the  molecules  is  the  means  by  which  an  organ- 
ism maintains  unity  amidst  changing  influences.  Death 
and  disintegration  result  whenever  the  internal  changes 
or  activities  are  not  of  the  right  kind  or  degree  to  maintain 
unity  among  environing  forces.  The  environing  influences 
may  modify  the  organism,  but  only  when  they  kill  it  or 
cause  it  to  cease  to  be  an  organism  do  they  prevent  it  from 
maintaining  its  unity.  The  germ  of  an  acorn  becomes  an 
oak,  if  it  lives,  and  nothing  else.     Even  when  a  part  of  a 


INTRODUCTION  7 

plant  or  animal  is  grafted  on  another,  the  tendency  to 
preserve  a  unity  of  the  original  type  of  organism  is  evident ; 
e.g.  a  peach  bud  or  branch  produces  peaches  though  grow- 
ing on  a  plum  tree. 

The  unity  of  an  inorganic  thing  is  also  static  as  compared 
with  that  of  an  organism,  which  is  dynamic.  It  simply 
resists  external  forces  for  a  greater  or  less  time,  instead  of 
giving  forth  and  taking  in  material  from  the  environment 
and  organizing  it  as  a  part  of  itself,  as  does  the  organism. 
The  unity  of  an  inorganic  thing  once  formed  is  not  changed 
except  in  a  destructive  way,  while  the  unity  of  an  organism 
varies  as  it  grows  and  passes  through  different  stages  of 
development.  Even  after  it  is  mature,  an  organism  is 
subject  to  some  modifications  in  its  characteristics  and 
modes  of  maintaining  unity. 

Again,  machines  and  molecules  do  not  reproduce  them- 
selves, while  organisms  not  only  maintain  their  own  unity 
but  produce  other  organisms  like  themselves.  This  is 
perhaps  the  most  distinctive  of  all  their  characteristics. 

Between  the  two  great  types  of  organisms,  plants  and 
animals,  there  is  no  absolute  distinction ;  but  in  general, 
plants  maintain  their  unity  by  taking  suitable  substances 
from  the  environment  and  building  them  into  their  own 
structure,  while  animals  take  in  objects  as  wholes,  disin- 
tegrate them,  incorporate  into  their  structure  what  is 
suitable,  and  excrete  the  rest.  Animals  not  only  use  the 
substance  taken  in  for  forming  their  structure,  but  they  also 
utilize  the  chemical  energy  set  free  by  molecular  changes 
in  maintaining  the  heat  of  the  organism  and  in  keeping 
its  various  mechanisms,  especially  the  muscular,  active ; 
while  plants  use  little  or  no  energy  in  the  movement  of 


8  *  GENETIC   PSYCHOLOGY 

organs  and  the  maintenance  of  heat.  Again,  plants  main- 
tain their  unity  chiefly  by  slow  growth  changes  that  bring 
them  more  favorable  and  less  unfavorable  stimulation 
and  more  usable  substances  which  are  simply  absorbed, 
while  animals  usually  preserve  their  unity  by  movements 
of  parts  or  all  of  the  body  in  such  ways  as  will  secure 
favorable  stimuli  and  avoid  unfavorable,  and  they  find 
and  secure  food,  disintegrate  and  distribute  it  to  different 
parts  of  the  body  by  the  actions  of  organs  (antennae,  feet, 
teeth,  intestines,  etc.)  specially  adapted  to  those  purposes. 

EVOLUTION  AND  THE  GENESIS  OF  BEHAVIOR  AND  OF  MIND 

The  problem  of  the  genesis  of  mind  is  simply  one  phase 
of  the  problem  of  evolution.  It  is  not  a  question  of  crea- 
tion, but  in  a  broad  sense,  one  of  how  organisms  are  formed 
in  nature's  w^orkshop  so  that  they  behave  in  certain  ways 
and  perhaps  exhibit  a  conscious  life. 

Starting  with  protoplasm,  which  is  simply  a  form  of 
matter  more  highly  organized  than  any  single  chemical 
molecule,  nature,  in  the  course  of  the  ages,  has  produced 
an  infinite  number  of  species  of  organisms,  each  of  which 
has  its  own  peculiarities  of  structure  and  behavior  and 
possibilities  of  being  modified  through  elimination  of  some 
individuals  and  the  reproductive  activities  of  survivors. 
Every  individual  w^hich  survives,  attains  a  certain  form  and 
size  and  acts  in  such  a  way  as  to  maintain  life  as  an  indi- 
vidual and  produce  descendants  by  which  the  species  is 
perpetuated. 

How  each  species  of  animals  came  to  have  its  charac- 
teristic size,  structure,  and  mode  of  behavior  is  the  problem 


INTRODUCTION  g 

of  evolution  and  of  genetic  psychology.  The  answer  to 
this  question  must  always  be  sought  in  the  history  of  the 
species  as  well  as  in  the  laws  of  chemical  and  physical 
activity.  The  chief  factor  to  be  recognized  in  studying 
the  history  of  the  species  is  expressed  by  the  words  "  natu- 
ral selection." 

The  way  in  which  this  factor  in  evolution  works  may  be 
illustrated  by  a  concrete  question,  the  answer  to  which  in 
one  case  has  been  experimentally  demonstrated.  Why  arc 
not  sparrows  as  large  as  geese  or  as  small  as  flies  instead  of 
being  just  about  the  size  they  are?  After  a  severe  storm 
a  large  number  of  sparrows  were  picked  up  in  a  helpless 
condition  and  as  many  as  possible  resuscitated.  All  were 
then  weighed  and  measured  to  determine  the  size  and 
proportion  of  parts.  It  was  found  that  nearly  all  that 
varied  to  any  considerable  degree  from  the  average  were 
dead,  while  most  of  those  near  the  average  in  all  respects 
were  alive.  This  of  course  means  that  a  certain  size  and 
proportion  of  parts  are  most  favorable  for  a  sparrow  living 
in  this  climate,  and  that  those  birds  that  vary  the  most 
from  the  normal  are  likely  to  be  destroyed  and  produce 
few  or  no  descendants.  In  a  different  environment  or  liv- 
ing a  different  life,  the  size  and  proportion  of  parts  of  the 
sparrow  might  be  different,  but  in  any  case  environment 
determines  through  natural  selection  the  size  of  sparrows 
living  in  a  certain  way  in  a  certain  place.  What  is  true 
of  the  size  of  the  sparrow  is  true  of  all  his  other  character- 
istics, including  his  behavior ;  for  if  he  attempted  to  do . 
what  his  structure  does  not  fit  him  to  do,  he  would  be  at 
a  disadvantage  and  would  be  eliminated  by  natural  selec- 
tion and  along  with  him  that  mode  of  sparrow  behavior. 


lO  GENETIC   PSYCHOLOGY 

What  is  true  of  sparrows  is  true  of  all  creatures ;  all  are 
destroyed  whose  modes  of  behavior  and  structure  do  not 
correspond  so  as  to  enable  them  to  maintain  proper  rela- 
tions with  the  environment.  In  studying  the  structure 
and  behavior  of  various  types  of  organisms  we  must  inter- 
pret them  as  means  of  survival  for  the  individual  or  for 
the  species,  and  we  must  expect  the  usual  behavior  to 
be  effective  in  proportion  as  the  conditions  under  which 
the  individual  acts  are  the  same  as  they  have  been 
for  his  ancestors  for  many  generations.  If  the~  con- 
ditions are  radically  different,  what  was  an  effective 
mode  of  maintaining  existence  may  be  useless  or  even 
destructive,  e.g.  it  is  of  advantage  for  sheep  to  follow  their 
leaders  on  their  native  plains,  but  in  the  mountains  they 
may  thus  be  led  over  a  precipice. 

So  far  we  have  indicated  only  how  organisms  having 
certain  characteristics  suitable  to  a  certain  mode  of  life 
and  environment  are  prevented,  while  the  species  remains 
under  those  same  conditions,  from  changing  their  charac- 
teristics in  any  considerable  degree.  Both  the  genetic 
and  the  complete  evolutionary  view,  however,  demand 
something  more. 

Evolutionary  theory  demands  that  we  shall  also  explain 
how  various  species  of  animals  have  changed  their  size 
and  characteristic  correlations  under  domestication,  and 
how  a  number  of  differing  specjes  in  a  natural  state  may 
have  developed  from  common  ancestors  instead  of  the 
original  characteristics  only  of  the  species  having  been 
preserved  by  natural  selection.  If  we  suppose  that  each 
type  of  organism  possesses  potential  characteristics  that 
may  either  be  made  prominent  or  suppressed,  then  without 


INTRODUCTION  II 

any  assumption  other  than  we  have  already  made,  we  may 
explain  such  transformations  either  by  changes  in  the  mode 
of  behavior  of  different  groups  of  the  common  species, 
which  necessitated  corresponding  changes  in  structure,  or 
by  different  groups  being  subjected  to  different  environ- 
ments so  that  characteristics  that  were  harmonious  in  one 
were  eliminated  in  another.  Some  species  of  sea  animals, 
for  example,  have  remained  practically  the  same  through 
many  geological  ages,  probably  because  their  environment 
and  mode  of  life  have  not  changed,  while  land  animals, 
exposed  to  great  variations  in  environment  due  to  lati- 
tude and  changing  elevation,  have  dift'erentiated  into  a 
great  variety  of  species,  living  and  extinct. 

Structure,  behavior,  and  intelligence  in  any  species  of 
animals  are  all  correlated  modes  of  insuring  survival  in  a 
given  environment  according  to  certain  modes  of  life  which 
have  remained  the  same  for  many  generations.  In  so 
far  as  the  conditions  are  uniform,  behavior  is  machine- 
like. Each  individual  may  be  regarded  as  a  typical  ma- 
chine formed  by  natural  selection  to  do  the  things  in  the 
given  environment  which  will  usually  secure  survival  for 
members  of  his  species.  The  mode  of  life  and  environment 
of  the  species  must  be  known  in  order  to  understand  the 
action  of  an  individual  organism,  just  as  we  must  know  the 
purpose  of  a  machine  and  the  materials  upon  which  it 
works  in  order  to  understand  it.  Genetic  psychology  must 
not  only  consider  these  correlations  in  different  species  and 
determine  common  principles  of  correlation  in  all  species 
from  the  simplest  to  the  most  complex,  but  it  must  also 
trace  the  changes  in  these  correlations  as  species  have 
developed  into  higher  forms  in  the  life  of  the  race.     It 


12  GENETIC   PSYCHOLOGY 

must  also  determine  the  relation  existing  between  the 
stages  of  development  of  the  individual  and  those  of  the 
race,  and  the  interaction  between  racial,  individual,  and  en- 
vironmental factors  in  the  life  of  the  individual. 

In  the  life  of  an  individual  organism,  however,  there  are 
many  changes  from  the  infantile  mode  of  maintaining  exist- 
ence to  that  of  the  mature  creature.  Every  change  in  struc- 
ture and  mode  of  life  must  be  accompanied  by  other  changes 
in  order  that  the  balance  upon  which  life  depends  shall  be 
preserved;  e.g.  various  muscles  must  have  developed  be- 
fore the  young  creature  can  successfully  change  from  a 
life  of  dependence  upon  parents  for  food  and  protection, 
to  that  of  complete  independence;  and  the  abandonment 
of  liquid  for  solid  food  by  the  human  infant  needs  to  be 
correlated  with  the  development  of  teeth.  One  of  the  chief 
problems  of  genetic  investigation  is  to  determine  just 
what,  in  detail,  are  the  normal  correlated  changes  in  struc- 
ture and  behavior  in  each  stage  of  development  of  the 
individual,  in  order  that  he  may  at  all  stages  be  in  harmony 
with  his  environment.  Natural  selection  has  no  doubt 
determined  what  these  correlations  are  at  each  stage  of 
development,  in  the  same  way  as  it  has  determined  the  cor- 
relations of  the  mature  individual,  but  with  slightly  less 
definiteness,  because  temporary  variations  are  less  likely 
to  result  in  death  than  permanent  ones. 

So  far  we  have  assumed  two  principles  upon  which 
evolutionary  theory  is  founded ;  that  of  like  producing 
like,  or  heredity,  and  that  of  variation,  because  of  which 
descendants  are  not  exactly  like  ancestors  and  not  exactly 
like  each  other.  The  last  gives  opportunity  for  natural 
selection  to  work  and  the  first  helps  to  perpetuate  what 


INTRODUCTION  I3 

natural  selection  has  caused  to  survive.  These  factors 
in  evolution  will  not  here  be  discussed  further  than  to  say 
that  the  chief  question  to  be  answered  is,  "What  are  the 
causes  of  variation?"  the  chief  points  in  dispute  being 
as  to  whether  environment  is  a  factor  in  producing  varia- 
tions as  well  as  in  destroying  inharmonious  ones,  and  as 
to  whether  variations  acquired  during  the  life  of  an  in- 
dividual are  transmitted  to  its  descendants. 


THE    PSYCHIC    FACTOR    IN    BEHAVIOR 

Since  we  know  nothing  of  the  conscious  states  of  animals 
except  by  inference,  it  is  best  to  seek  to  explain  just  as  much 
as  possible  of  the  behavior  of  all  organisms  from  the  lowest 
to  the  highest  without  presupposing  the  psychic  factor. 
When  we  can  find  nothing  similar  to  our  unconscious 
physiological  instinctive  and  habitual  behavior  by  which 
the  behavior  of  any  creature  may  be  explained,  then  we 
are  justified  in  trying  an  explanation  that  involves  con- 
scious states  similar  to  our  own.  Whether  consciousness 
is  or  is  not  an  element  in  any  particular  form  of  behavior 
is  to  be  determined  by  the  facts  rather  than  by  presup- 
positions, but  it  is  safer  not  to  assume  conscious  states 
until  all  the  simpler  and  more  demonstrable  factors  in 
behavior  have  been  given  due  weight. 

At  the  same  time  we  are  to  retain  the  right  to  suppose 
consciousness  an  effective  factor  in  behavior  whenever 
necessary.  It  is  reasonable  to  believe  that  this,  like  all 
other  characteristics  of  organisms,  is  the  product  of  natural 
selection,  and  that  it  has  been  preserved  in  certain  kinds 
of  behavior  of  certain  organisms  because  it  has  proved 


14  GENETIC   PSYCHOLOGY 

useful.  Of  course,  if  one  chooses  to  suppose  that  conscious- 
ness, like  protoplasm,  is  an  element  in  all  organisms  and 
in  every  organic  activity  of  plant  or  animal,  it  is  useless  to 
dispute  his  claim,  but  we  should  still  be  governed  by  the 
same  principle  of  using  conscious  states  like  our  own  as 
explanations  of  behavior  only  when  the  behavior  can  be 
explained  in  no  other  way.  Even  if  we  admit  that  con- 
sciousness is  present  in  some  form  in  all  organic  activity 
we  must  not  allow  ourselves  to  believe  that  the  conscious- 
ness is  like  that  we  experience  until  such  a  supposition 
gives  the  most  probable  explanation  that  we  can  obtain. 

The  habit  of  explaining  our  own  actions  and  those  of 
others  in  terms  of  consciousness  is  so  strong  that  it  is  hard 
to  avoid  thinking  of  conscious  states  as  the  cause  of  the 
behavior  of  organisms,  and  when  one  does  resist  the  tend- 
ency, it  is  often  hard  to  find  terms  not  implying  conscious- 
ness in  which  to  describe  clearly  and  briefly  the  behavior 
of  even  the  simplest  creatures.  A  special  set  of  terms  is 
needed  for  this  purpose,  but  in  the  absence  of  any  that 
are  well  known,  we  shall  try  to  make  our  meaning  clear 
by  using,  when  necessary,  old  psychical  terms  with  broader 
meanings. 

REFERENCES 

*Angell.     Psychology,  Chapter  I. 

Baldwin.     Mental  Development,  Methods  and  Processes,  Chapter  I. 

Baldwin   and   Cattell.     Consciousness   and   Evolution,  Science 

(N.S.),  Vol.  II,  pp.  219-223. 
*BuMPUS,  H.  C.     Elimination  of  the  Unfit,  Biological  Lectures  at 

Wood's  Hole,  1897-1898,  pp.  209-226. 
Carus,  p.  The  Soul  of  Man,  pp.  54-65. 
*Conn,  H.     W.   The  Story  of  the  Living  Machine. 


INTRODUCTION  15 

Davies,  Ernest.     Suggestions  toward  a  Psychogenetic  Theory  of 

Mind,  Jr.  Phil.  Psych.  &=  Sci.  Meth.,  Vol.  IV,  pp.  342-356. 
*Hall,  G.  S.     a  Glance  at  the  Philetic  Background  of  Psychology, 

Am.  Jr.  Psych.,  Vol.  XIX,  pp.  149-212. 
Herrick,  C.  L.     The  Nature  of  the  Soul  and  the  Possibility  of  the 

Psycho-Mechanic,  Psych.  Rev.,  Vol.  XIV,  pp.  205-228. 
■ Genetic  Modes  and  the  Meaning  of  the  Psychic,  Psych.  Rev., 

Vol.  XIV,  pp.  54-59- 
*HoBHOUSE,  L.  T.     Mind  in  Evolution,  Chapters  I  and  II. 
*JuDD.     Psychology,  Chapter  I. 
Kjrkpatrick,  E.  a.     a  Broader  Basis  for  Ps3'chology  Necessary, 

/;-.  Phil.  Psych,  b' Sci.  Meth.,  Vol.  IV,  pp.  542-546. 
*Moore,  J.  H.     The  Universal  Kinship. 
Mills,  W.     Animal  Intelligence,  Chapter  I. 
♦Morgan,  L.     Comparative  Psychology,  Chapter  III. 

Animal  Life  and  Intelligence,  Chapter  I. 

Comparative  and  Genetic  Psychology,  Psych.  Rev.,  Vol.  XII, 

pp.  78-97. 
Romanes,  G.  J.     Mental  Evolution  in  Animals,  Chapter  I. 
*Washburn.     The  Animal  Mind,  Chapter  I. 
*Wundt.     Human  and  Animal  Psychology,  Chapter  XXIII. 


CHAPTER   II 

STRUCTURAL  BASIS   OF  BEHAVIOR 

GENERAL   PRINCIPLES 

Just  as  any  movement  made  by  a  machine  is  determined 
by  the  nature  of  its  parts  and  their  relation  to  each  other, 
so  also  must  the  behavior  of  an  organism  be  the  result  o^ 
its  structure.  In  the  lowest  organisms,  such  as  the 
amoeba,  there  is  little  permanency  of  form,  and  action 
differs  somewhat  according  to  the  form  the  creature  has 
at  the  moment.  In  higher  animals  structure  is  compara- 
tively permanent,  though  subject  to  gradual  growth  or 
decline. 

Such  structures  as  bones  are  relatively  rigid,  while  other 
parts,  notably  muscular  and  nervous  tissue,  are  more  or 
less  easily  and  permanently  changed  in  their  size  and  re- 
lation to  each  other  by  repeated  and  sometimes  by  single 
experiences.  Where  the  various  nervous  and  muscular  ap- 
paratus are  grouped  into  only  slightly  connected  reflex 
mechanisms,  the  modifications  produced  by  experience 
are  comparatively  slight. 

If  an  animal's  behavior  is  dependent  upon  the  action  of 
fixed  structures  it  must,  in  order  to  survive,  either  come 
into  helpful  and  harmful  relations  with  a  very  few  phases 
of  its  environment,  or  else  it  must  possess  a  great  many 
varieties  of  fixed  structures  with  which  to  make  the  right 

i6 


STRUCTURAL   BASIS   OF    BEHAVIOR  17 

reaction  to  the  various  situations  that  affect  it  favorably 
or  unfavorably.  As  a  matter  of  fact,  most  organisms, 
like  many  machines,  instead  of  having  an  apparatus  for 
each  thing  to  be  done,  are  capable  of  a  variety  of  adjust- 
ments for  various  purposes  and  to  meet  varying  situations. 
A  creature  possessing  a  small  number  of  fixed  structures, 
yet  having  a  mechanism  by  means  of  which  the  different 
parts  may  be  made  to  act  in  various  combinations  to  meet 
a  great  variety  of  situations,  is  fitted  to  survive  in  an  en- 
vironment affecting  it  in  many  ways. 

If,  in  addition  to  the  natively  possible  adjustments, 
the  creature  is  so  made  that  combinations  that  have  had 
favorable  results  are  more  readily  made  again,  then  the 
individual  animal  can  quickly  adapt  itself  to  new  phases 
of  its  environment.  As  we  shall  see,  the  fundamental 
characteristics  of  all  organisms  are  similar.  The  higher 
organisms  can  do  many  things  that  the  lower  cannot,  and 
they  are  often  able  to  reach  the  same  results  in  more  eco- 
nomical ways.  This  is  not  because  they  are  composed  of 
substances  of  an  entirely  different  character  or  because 
they  possess  many  varieties  of  apparatus,  but  because  of 
specialization  in  structure  and  more  complete  correlation 
and  cooperation  between  parts.  We  must  therefore  take 
a  very  general  view  of  the  specialization  in  structure  upon 
which  the  behavior  of  animals  depends. 

SPECIALIZATION   OF   SENSITIVE   STRUCTURES 

The  skin  of  man,  like  the  surface  of  the  amoeba,  re- 
sponds to  electrical,  chemical,  mechanical,  and  thermal 
stimulation.     In  the  amoeba  all  parts  respond  equally, 


1 8  GENETIC   PSYCHOLOGY 

while  in  man  and  the  higher  animals  some  parts  are  much 
more  sensitive  than  others.  JNIOreover,  the  parts  most 
sensitive  to  one  kind  of  stimulus,  as  heat,  may  be  less  so 
to  another,  as  pressure.  No  organism,  whether  possess- 
ing nervous  tissue  or  not,  is  insensitive  to  these  fundamental 
stimuli. 

Nearly  all  possess  some  specialized  touch  apparatus  for 
responding  to  mechanical  stimulations,  and  the  same 
apparatus  is  frequently  quite  sensitive  to  other  kinds  of 
fundamental  stimuli.  This  touching  surface  is  always 
correlated  with  the  form  of  the  animal  and  its  habits  of  life 
in  a  given  environment.  In  most  creatures  the  whole  of 
the  surface  is  sensitive  in  some  degree  to  mechanical 
stimulation,  but  the  parts  near  the  mouth  are  usually  most 
sensitive.  Movable  parts  are  especially  sensitive,  particu- 
larly those  that  are  likely  to  be  stimulated  in  moving  around 
in  search  of  food. 

In  creatures  having  a  hard  and  comparatively  insensitive 
surface,  like  crabs  and  beetles,  there  are  usually  special 
touch  organs  at  the  anterior  end  in  the  form  of  antennae. 
These  parts  are  usually  very  sensitive,  not  only  to  contact 
and  pressure,  but  also  to  other  fundamental  forms  of  stimu- 
lation. In  mammals  the  tongue  and  lips  are  most  sensi- 
tive of  all  portions  of  the  skin  to  contact  and  pressure. 
These  parts  are  also  sensitive  in  a  general  way,  like  the 
rest  of  the  skin,  to  other  fundamental  stimuli. 

in  addition  to  this,  certain  portions  of  the  tongue  and 
mouth  are  provided  with  special  forms  of  nerve  endings 
that  are  sensitive  in  a  special  degree  to  chemical  stimuli 
that  in  man  give  sensations  of  sweet,  salt,  sour,  and  bitter. 
Specialized   organs  of  taste  are  found  in  all  the  higher 


STRUCTURAL    BASIS    OF   BEHAVIOR  1 9 

vertebrates,  but  are  not  easily  demonstrated  in  fishes  and 
frogs,  though  the  Crustacea  and  worms  act  as  though  they 
possessed  such  organs.  By  means  of  these  sensitive  sur- 
faces particles  unsuitable  for  food  are  discriminated  and 
rejected  more  effectively  than  would  be  possible  with  a 
surface  sensitive  to  contact  only. 

Near  the  mouth  is  often  found  a  specialized  surface  that 
is  particularly  sensitive  to  other  kinds  of  chemical  stimuli 
than  those  of  taste.  Stimulation  of  this  surface  in  man 
gives  rise  to  the  various  sensations  of  smell.  The  organs  for 
receiving  these  stimuli  conveyed  to  them  in  the  air  do  not 
appear  to  be  at  all  complex  in  structure,  but  they  are  won- 
derfully sensitive,  being  excited  by  smaller  amounts  of 
matter  than  any  other  sense  organ,  and  giving  rise  to  an 
immense  variety  of  specifically  different  sensations.  The 
olfactory  apparatus  is  much  larger  in  a  great  many  animals 
than  in  man.  In  fishes  and  other  aquatic  animals  it  is 
sometimes  very  large,  but  as  the  stimulus  must  come  to 
them  in  liquid  form  the  sense  is  probably  more  allied  to 
taste  than  to  smell. 

With  a  well-developed  olfactory  apparatus  an  animal 
can  react  not  only  to  objects  that  are  in  actual  contact 
with  it  but  to  emanations  that  are  in  a  way  samples  of 
objects  at  a  considerable  distance.  He  is  thus  greatly 
aided  in  escaping  danger  and  in  finding  food.  Water  ani- 
mals provided  with  the  proper  sensitive  apparatus,  whether 
it  be  called  a  taste  or  smell  organ,  may  also  react  to  ob- 
jects not  in  contact  with  them,  though  not  when  they  are 
at  such  great  distances. 

Taste  and  smell  are  usually  classed  together  as  chemical 
senses  and  the  biological  purposes  they  serve  are  evidently 


20  GENETIC   PSYCHOLOGY 

similar.  Even  in  man  these  two  senses  are  not  clearly 
differentiated  from  each  other  or  from  contact  and  tem- 
perature sensations.  Coffee  and  ice  cream  are  relished 
only  when  all  three  senses  are  properly  stimulated,  al- 
though we  usually,  perhaps,  think  of  taste  as  the  only 
sense  involved. 

Light  is  primarily  a  chemical  stimulus  of  slight  intensity. 
It  is  responded  to  more  or  less  quickly  by  creatures  with- 
out any  specialized  surface  for  its  reception  and  by  some 
creatures,  such  as  worms,  after  their  visual  organs  have  been 
cut  out.  In  this  condition  they  may  respond  not  only  to 
variations  in  light  intensity,  but  also,  as  Graber  showed,  to 
rays  of  different  vibration  length,  since  they  come  to  rest 
chiefly  in  one  colored  compartment  rather  than  those  of 
other  colors.  In  such  animals  all  the  life  processes  are 
probably  increased  or  decreased  by  changes  in  light  in- 
tensity and  the  effects  of  waves  of  certain  length  are 
greater  than  those  of  others.  In  general,  animals  that  seek 
the  light,  or  in  other  words  are  positively  phototropic,  are 
likely  to  go  to  the  ultra  violet  end  of  the  spectrum,  while 
those  that  avoid  the  light,  or  the  negatively  phototropic, 
move  toward  the  red  end  of  the  spectrum  when  light 
cannot  be  avoided. 

The  most  primitive  special  organ  for  responding  to 
light  stimulation  is  only  a  slightly  modified  portion  of  the 
touch  organ,  skin,  or  tentacle  that  is  more  sensitive  than  the 
rest  to  variations  in  light  intensities.  The  pigmented  eye 
spots  of  the  starfish  are  organs  of  this  type.  With  such 
organs  an  animal  can  react  to  the  shadow  of  an  object  that 
has  not  yet  touched  it,  as  does  the  clam,  because  of  the 
variation  in  light  intensity  produced  by  the  approaching 


STRUCTURAL    BASIS    OF    BKHAVIOR  21 

or  the  approached  opaque  objects.  In  such  cases  the 
reaction  is  not  due  so  much  to  the  immediate  chemical 
effects  of  variation  in  light  stimulation  upon  the  whole 
organism  as  to  the  excitation  of  a  sensitive  apparatus  that 
then  causes  a  motor  apparatus  to  move  a  part  or  all  of  the 
body.  Some  animals  thus  respond  to  variations  in  light  in- 
tensity caused  by  objects,  although  no  shadow  is  produced. 
If  objects  of  a  certain  color  in  the  environment  are 
usually  injurious  or  helpful,  then  all  individuals  but  those 
most  sensitive  to  this  stimulus  will  be  eliminated  by  natural 
selection.  We  may  suppose  therefore  that  sensitiveness  to 
different  kinds  of  light  stimulation  in  any  species  of  animals 
depends  upon  what  kinds  of  light  stimulation  it  has  been 
most  necessary  for  it  to  respond  to  in  its  usual  environment. 
Yerkes'  experiments  prove  that  light  rays  do  not  always  pro- 
duce the  same  relative  effects  on  animals  as  on  man.  He 
found  that  two  colors  of  the  same  brightness  to  human 
eyes  were  reacted  to  as  if  different  by  Japanese  mice,  while 
colors  of  differing  brightness  to  human  eyes  were  responded 
to  by  the  mice  as  if  they  were  the  same.  We  know  in  our 
own  case  that  some  colors  are  distinguishable  in  a  dim 
light  more  easily  than  others.  The  same  is  true  of  periph- 
eral compared  with  foveal  vision.  Probably  it  is  more 
useful  to  discriminate  some  colors  in  a  dim  illumination 
than  others.  The  visual  apparatus  of  each  creature 
doubtless  fits  it  for  discriminating  significant  stimulations 
under  the  usual  conditions  in  which  the  species  lives.  For 
all  species  to  discriminate  brightness,  is  probably  more 
important  than  to  discriminate  colors ;  hence  organs  for 
responding  to  brightness  develop  earlier  than  those  for 
responding  to  special  colors. 


22  GENETIC   PSYCHOLOGY 

Moving  objects  are  in  general  more  significant  to  animals 
than  motionless  ones,  hence  we  find  that  the  more  primi- 
tive organs  of  vision  are  especially  adaj^tecl  to  the  percep- 
tion of  motion,  a  condition  retained  in  the  periphery  of  the 
human  eye.  In  many  of  the  lower  animals  reaction  to 
the  stimulus  of  a  moving  object  is  made  possible  by  the 
possession  of  many  simple  eyes  or  by  compound  eyes. 
Insects  possessing  compound  eyes  appear  to  discriminate 
stationary  objects  of  different  colors,  yet  their  own  motion 
and  the  difference  in  the  brightness  of  the  colors  may  be 
the  chief  factors,  and  there  may  be  no  color  or  form  per- 
ception of  stationary  objects  when  the  creature  is  at  rest 
and  the  object  not  moving. 

Animals  that  react  to  objects  of  different  colors,  such  as 
fish,  insects,  and  higher  animals,  have  lenslike  structures 
over  the  portion  specialized  to  respond  to  light  stimula- 
tions, which  concentrate  the  rays  upon  this  more  sensitive 
part,  thus  increasing  the  effects  of  the  stimulus.  In  the 
invertebrate  eye  the  lens  concentrates  the  rays  of  light, 
but  in  general  the  nerve  fibers  going  to  the  eyes  do  not 
cross.  In  the  vertebrate  eye  the  pigment  layers  are  behind 
the  nerve  fiber  layer  and  at  least  a  portion  of  the  fibers 
cross,  which  probably  makes  possible  some  use  of  the 
two  eyes  together.  In  some  instances  the  eyes  are  so 
located  that  both  may  be  affected  by  the  same  object  while 
in  others  they  are  not.  When  they  do  not  have  almost  the 
same  field  of  view  they  are  usually  nearly  stationary  in  the 
head,  and  the  head  or  the  whole  body  must  be  moved  to 
get  a  change  of  view  and  perhaps  any  perception  of  form 
of  the  stationary  object.  It  is  not  likely  that  chickens, 
for  example,  have  a  clear  perception  of  the  outline  of 


STRUCTURAL   BASIS   OF   BEHAVIOR  23 

objects.  Their  perceptions  and  those  of  most  birds  and 
mammals  are  probably  no  more  clearly  defined  than  is 
one's  perception  of  the  exact  outlines  of  an  object  in  a  fog 
or  in  semi-darkness. 

The  retina  of  the  lower  vertebrates  is  relatively  undiffer- 
entiated, only  the  rodlike  structure  of  the  retina  being 
present ;  while  in  the  higher,  there  arc  both  rods  and  cones 
and  they  are  much  more  crowded  together  near  the  fovea. 
This  differentiation  of  the  sensitive  visual  surface  is  prob- 
ably necessary  to  clear  vision  of  stationary  objects  and  to 
the  perception  of  specific  colors,  since  cones  seem  to  be 
the  special  organs  for  discrimination  of  color  differences. 
Experiments  upon  man  show  that  only  when  both  the  ob- 
ject and  the  eyes  are  nearly  stationary  can  the  form  of  the 
object  be  clearly  seen,  although  the  mere  presence  of  objects 
is  more  readily  discovered  when  they  or  the  eyes  are  moved. 

In  man's  activities,  form  is  of  great  significance  and  there 
is  good  reason  to  believe  that  he  discriminates  form  far 
more  perfectly  than  other  animals.  This  is  made  possible 
by  the  wonderful  optical  instrument  with  which  he  is 
furnished.  As  a  lens  for  bending  the  rays  of  light  it  is 
probably  no  better  than  that  of  many  animals,  but  the 
retina  presents  more  variations  between  the  fovea  and  the 
periphery  than  are  found  in  any  other  animal.  This, 
with  the  power  of  accommodation  for  different  light  in- 
tensities and  distances  of  objects,  and  the  power  of  accurate 
fixation  and  movement  of  the  two  eyes  so  as  to  make  the 
two  images  combine,  renders  it  possible  to  perceive  the 
form  of  stationary  objects  with  wonderful  accuracy. 

In  its  fundamental  nature,  sound  stimulation  is  pro- 
duced by  waves  of  air  or  liquid,  instead  of  objects,  striking 


24  GENETIC    PSYCHOLOGY 

a  sensitive  surface.  Probably  all  portions  of  organisms 
that  are  sensitive  to  mechanical  stimuli  are  sensitive  to 
sound  stimuli  in  some  form  or  in  some  degree.  Certain 
it  is  that  deaf  people  not  only  feel  jars  but  can  enjoy 
music  through  the  fingers  resting  on  a  piano  or  other 
vibrating  surface.  Helen  Keller  also  readily  distinguishes 
the  vibrations  caused  by  the  step  or  voice  of  a  child  from 
those  of  an  adult.  Some  of  the  lov^er  organisms  react  to 
a  jar  just  as  they  would  to  a  touch  on  their  most  sensitive 
surface.  The  simplest  form  of  specialized  organ  is  the 
otocyst,  which  contains  stonelike  bodies  that  when  set  in 
motion  stimulate  the  auditory  nerve.  Organs  of  this  same 
general  character,  called  statoliths,  surrounded  by  liquid, 
serve  also  as  a  means  of  maintaining  equilibrium,  being 
stimulated  by  variations  in  the  pressure  of  the  liquid,  as 
the  animal  moves. 

In  some  creatures  that  make  sounds,  and  therefore 
probably  hear,  organs  of  hearing  are  not  easily  demon- 
strated. In  the  case  of  fishes,  frogs,  and  higher  animals, 
when  the  organs  of  hearing  are  clearly  present,  it  is  often 
difficult  to  get  definite  responses  to  sound  stimulations. 
Yerkes  could  not  get  from  frogs  any  response  to  any  kind 
of  sound  stimulation  given  alone  under  laboratory  condi- 
tions, though  a  sound  stimulus  was  found  to  modify  the 
reactions  of  the  frog  to  other  stimuli  that  were  being  given 
at  the  same  time.  The  observations  of  Courtis  show  that 
frogs  in  the  mating  season  respond  to  the  call  of  mates. 
Yerkes  obtained  response  from  Japanese  mice  to  auditory 
stimuli  only  from  young  animals  for  a  few  days  at  a  certain 
stage  of  their  development,  and  he  could  obtain  no  response 
from  adult  animals. 


STRUCTURAL   BASIS   OF   BEHAVIOR  2$ 

Sounds  that  arc  not  very  intense  are  in  themselves 
neither  harmful  nor  helpful  to  most  animals,  and  since  a 
large  proportion  of  sounds  are  rarely  or  never  followed  by 
stimuli  that  are  either  harmful  or  helpful  to  many  species 
of  animals,  it  would  be  a  useless  waste  of  energy  to  react 
to  every  sound.  Most  animals  therefore  do  not  respond 
to  most  sounds  unless  they  are  very  loud  or  sudden.  The 
sounds  that  they  do  most  surely  rcsj)ond  to  are  those  that 
in  the  life  of  the  species  have  usually  meant  unfavorable 
or  favorable  stimuli  to  follow.  We  find  therefore  that  the 
sounds  most  surely  reacted  to  are  the  calls  and  cries  of 
companions  signifying  food,  danger,  or  the  presence  of  a 
mate.  Sounds  made  by  enemies,  e.g.  the  rattlesnake, 
and  by  prey,  are  also  frequently  reacted  to  instinctively; 
but  most  other  sounds  bring  no  response,  unless  sudden, 
intense,  or  of  a  kind  that  in  individual  experience  has  been 
associated  with  unfavorable  or  favorable  results. 

Sounds  repeated  again  and  again  rhythmically,  as  in 
music,  are  reacted  to  by  both  animals  and  man,  though 
they  are  not  suggestive  of  any  stimulus  to  follow.  This 
is  probably  because  there  is  summation  of  the  slight 
stimuli  on  account  of  the  rhythm,  so  that  the  vibrations 
set  up  in  the  nerves  spread  to  the  muscles,  which  then 
produce  either  rhythmic  movements  or  a  balanced  con- 
traction of  parts  that  keeps  the  body,  as  a  whole,  still. 
Even  in  us  this  is  more  a  mechanical  and  physiological 
result  than  it  is  a  psychical,  for  we  can  often  keep  time  more 
perfectly  in  an  involuntary  than  we  can  in  a  voluntary  way. 
The  effect  of  strong  or  rhythmical  sound  stimulation  is  a 
mechanical  effect  comparable  to  the  chemical  effect  of 
light  stimulation  of  strong  intensity.  It  may  also  produce 
important  physiological  changes  as  light  does. 


26  GENETIC   PSYCHOLOGY 

The  anatomy  of  the  ear  of  higher  animals  is  more  com- 
plex in  its  adaptation  for  the  reception  of  stimulation 
than  any  other  sense  organ.  There  is  an  external  ear  for 
catching  the  sound  vibrations,  a  middle  ear  for  intensifying 
their  effects,  and  a  very  complex  structure  in  the  internal 
ear,  not  yet  fully  understood,  for  receiving  vibrations  of 
different  lengths  and  exciting  nerve  endings.  Though 
suited  to  respond  to  vibratory  motion,  the  organ  as  a  whole 
is  not  movable  as  is  the  eye.  Animals  whose  safety  de- 
pends upon  perceiving  the  direction  of  a  sound  usually 
have  the  external  ear  movable.  In  man  the  motion  needed 
to  determine  the  direction  of  sound  stimulation  is  effected 
by  means  of  the  muscles  of  the  neck. 

Since  the  ear  cannot,  like  the  eye,  shut  out  stimulation 
and  cannot  of  itself  react  in  a  motor  way,  its  stimulation 
is  naturally  more  closely  connected  with  the  muscles  con- 
trolling the  vocal  organs  than  with  other  parts  of  the  body. 
Since  there  is  not  usually  a  sufficient  immediate  motor 
outlet  for  the  effects  of  sound  stimulation,  and  since  sum- 
mation effects  are  possible,  it  is  not  strange  that  more  in- 
tense feeling  may  be  produced  by  sound  stimulation  than 
by  visual. 

SUGGESTIVE    STIMULI 

It  is  worthy  of  note  that  the  most  highly  developed  sense 
organs  are  not  those  of  most  fundamental  importance  in 
the  life  processes,  not  those  stimulated  directly  by  the  ob- 
jects themselves,  not  those  that  receive  immediately  useful 
or  harmful  stimuli,  but  those  that  receive  chiefly  what  may 
be  designated  as  ^^  suggestive  stimuli,"  which  are  not  in 
themselves  favorable  or  unfavorable.     It  is  also  to  be 


STRUCTURAL    BASIS   OF   BEHAVIOR  27 

noted  that  it  is  not  simj^ly  the  sensitive  surface  itself  that  is 
highly  specialized  for  the  senses  of  sight  and  hearing,  but 
the  apparatus  for  conducting  the  stimulus  to  the  sensitive 
surface  and  intensifying  its  effects.  Why  is  this  ?  Prob- 
ably because  elaboration  of  sense  organs  for  receiving 
stimuli  from  objects  with  which  the  creature  comes  in 
contact  is  not  necessary,  since  there  is  little  that  is  useful 
to  do  except  to  get  into  closer  contact  with  the  stimulus 
already  being  received  or  move  away  from  it,  according 
as  it  is  immediately  helpful  or  injurious.  Mechanical 
stimuli  can  vary  significantly  in  only  a  few  directions  and 
the  same  is  true  of  taste  stimuli.  Hence  an  organ  giving 
a  great  variety  of  sensitiveness  is  not  in  either  case  neces- 
sary. 

In  general,  the  reaction  of  higher  animals  to  the  visual 
stimulus  of  objects  is  not  a  direct  reaction  to  the  chemical 
stimulus,  which  in  itself  is  only  slightly  different  for  differ- 
ent objects,  but  the  visual  stimulus  is  suggestive  of  some 
other  more  intense  stimulus  of  a  favorable  or  unfavorable 
character.  The  suggestive  stimulus  is  therefore  reacted 
to  in  much  the  same  way  as  if  the  frequently  associated 
and  more  intense  stimulus  were  actually  given,  as  when, 
for  example,  the  head  is  drawn  back  as  if  struck,  when  a 
moving  object  suddenly  appears  in  front.  Reactions  to 
all  but  the  most  intense  sounds  are  also  almost  universally 
of  this  character. 

Where  the  life  of  the  species  has  been  such  that  a  certain 
visual  or  auditory  stimulus  has  nearly  always  been  fol- 
lowed by  something  that  was  harmful  or  helpful,  those 
animals  that  do  not  resj)ond  to  the  suggestive  stimuli  are 
soon  eliminated   from  the  species  by  natural  selection. 


28  GENETIC   PSYCHOLOGY 

The  scattering  and  seeking  of  cover  by  chickens  when  an 
object  comes  quickly  from  above,  is  a  good  example  of 
the  characteristic  reaction  of  all  members  of  the  species 
to  a  suggestive  stimulus  that,  in  the  life  of  the  race,  has 
frequently  been  followed  by  the  attack  of  an  enemy. 

Nearly  all  learning  in  the  case  of  higher  animals  and  in 
the  case  of  human  beings,  in  so  far  as  it  is  of  a  sensory 
motor  character,  is  in  the  nature  of  the  acquisition  of  a 
reaction  to  a  suggestive  stimulus  of  some  kind  that  has 
usually  brought  with  it  either  favorable  or  unfavorable 
results. 

Smell  acts  at  a  distance  from  the  main  bulk  of  the  stimu- 
lating body  so  that  time  is  given  for  a  complicated  and  varied 
sei-ies  of  movements  before  the  stimulating  object  itself 
can  do  harm  or  good.  The  olfactory  organ  is,  therefore, 
wonderful  in  its  power  to  respond  in  a  specific  way  to  a 
great  variety  of  objects  which  are  likely  to  be  injurious 
or  helpful  to  the  creature  if  it  comes  in  actual  contact  with 
them.  No  elaborate  external  structure  is  provided  for 
this  purpose,  but  there  is  such  great  differentiation  of  nerve 
endings  in  the  nose  and  the  brain  that  an  immense  number 
of  chemical  stimulations  significant  in  the  animal's  life 
may  be  responded  to. 

In  the  case  of  the  suggestive  senses,  sight  and  hearing, 
distant  objects  of  all  kinds  may  give  stimulations  and  the 
slightest  variations  in  their  character  may  be  of  the  great- 
est significance  in  determining  the  favorable  or  unfavor- 
able character  of  the  distant  object.  Hence  elaborate 
and  complex  structures  are  necessary  in  order  that  these 
slight  variations  may  be  detected  and  reacted  to  in  the 
proper  relations.     The  number  of  significant  objects  in 


STRUCTURAL   BASIS   OF   BEHAVIOR  29 

the  environment  revealed  to  creatures  possessing  such  sense 
organs  is  so  great  that  it  would  be  impossible  to  have  a 
single  characteristic  kind  of  response,  as  in  the  case  of 
smell.  Hence  these  senses  respond,  not  in  a  specific  way 
for  each  class  of  objects  as  does  smell,  but  to  an  infinite 
number  of  variations  and  combinations  of  a  few  elements. 
For  example,  in  odor,  a  dog  and  a  mouse  are  doubtless 
specifically  different  to  a  cat,  whether  they  are  near  or 
distant,  large  or  small,  stationary  or  moving;  but  in  the 
visual  sensations  they  cause,  a  dog  and  a  mouse  are  not 
specifically  different,  but  the  appearance  of  the  two  animals 
varies  according  to  their  nearness,  position,  and  move- 
ments, and  the  direction  and  the  intensity  of  the  light. 
It  is  not  any  one  quality  by  which  they  are  distinguished 
but  the  peculiar  combination  of  qualities  presented  in  any 
given  situation. 

The  visual  and  auditory  organs  are  wonderful  structures 
for  intensifying  a  few  varieties  of  stimulations  and  co}n- 
bining  them  in  many  ways,  while  the  olfactory  organ  is  a 
marvelous  structure  for  responding  to  a  great  variety  of 
specifically  different  stimulations,  but  it  can  do  little  or 
nothing  in  the  way  of  combining  them.  Speaking  figura- 
tively, it  gives  samples  of  objects  while  the  eye  and  the 
ear  give  letters  which  may  be  combined  in  an  infinite 
variety  of  ways  into  words  signifying  objects. 

Man  has  found  no  mechanical  means  of  making  the 
organs  of  touch,  taste,  and  smell  more  effective,  and  it  is 
probably  neither  desirable  nor  possible  that  he  should  do 
so.  On  the  other  hand,  the  suggestive  sense  organs  of 
sight  and  hearing  have  had  their  effectiveness  wonderfully 
increased  by  inventions  that  have  brought  us  into  relation 


30  GENETIC   PSYCHOLOGY 

with  an  environment  of  the  almost  infinitely  small  and 
almost  infinitely  distant.  Defects  in  these  organs  may  also 
be  corrected  by  artificial  means,  but  little  or  nothing  can 
be  done  by  any  mechanical  de\ice  to  correct  defects  in  the 
senses  of  touch,  taste,  or  smell. 

SOMATIC   AND   KINiESTHETIC   SENSE   STRUCTURES 

Although  the  greatest  specialization  of  sensitive  surface 
is  shown  in  the  special  sense  organs  that  are  portions  of 
the  surface  of  the  body,  it  must  not  be  forgotten  that  there 
are  special  sensitive  structures  within  all  the  vital  organs 
that  are  stimulated  by  changing  conditions  and  activities 
of  those  parts,  so  that  one  organ  may  respond  in  an  appro- 
priate way  to  changes  taking  place  in  other  parts  of  the 
body  and  thus  equilibrium  and  unity  of  life  processes  be 
maintained. 

These  internal  sensitive  structures  relate  the  organism  as 
a  whole  in  an  indirect  way  to  its  environment  by  respond- 
ing to  variations  in  the  amount  of  food  and  air  in  the  body, 
by  sensations  of  hunger,  thirst,  suffocation,  exhilaration, 
fatigue,  etc.  Many  of  these  somatic  sensitive  responses 
rarely  or  never  produce  conscious  sensations,  though  they 
are  doubtless  all  the  time  playing  an  important  part  in  the 
physiological  processes  involved  in  adjustments  of  circula- 
tory, respiratory,  and  digestive  activities,  and  indirectly 
affecting  conscious  states. 

There  are  also  certain  sensitive  structures  located  chiefly 
in  the  movable  portions  of  the  body  that  are  concerned 
in  the  direction  of  movements,  sometimes  called  kinesthetic 
sense  organs.     There  is  some  question  about  the  existence 


STRUCTURAL   BASIS   OF   BEHAVIOR  31 

of  these  structures  in  the  muscles  themselves,  but  they 
are  readily  perceived  in  the  attachments  of  muscles  and 
bones  and  in  joint  surfaces.  These  sensitive  structures 
are  stimulated  not  so  much  by  external  objects  or  by  in- 
ternal conditions  as  by  the  activity  of  the  movable  parts 
as  they  react  to  external  things.  They  are  therefore  espe- 
cially important  in  responding  to  external  stimulations 
appropriately,  according  to  the  space  relations  of  the  body 
and  its  parts  to  each  other  and  to  surrounding  objects. 

THE   DEVELOPMENT   OF    MOTOR   STRUCTURES 

No  improvement  in  sensitiveness  can  be  of  any  advantage 
to  a  creature  unless  it  has  also  a  motor  apparatus  capable 
of  a  corresponding  delicacy  of  movement.  We  must  expect 
therefore  a  close  correspondence  between  sensory  refine- 
ment and  motor  complexity.  Some  of  the  lower  animals, 
such  as  crabs,  squids,  and  millepeds,  have  many  movable 
parts,  one  serving  one  purpose  and  one  another.  In  the 
higher  animals  there  are  fewer  prominent  organs  of  move- 
ment but  much  more  cooperation  of  the  parts  in  perform- 
ing each  of  various  movements.  Not  only  do  the  limbs 
cooperate  with  each  other  in  the  higher  birds  and  mammals, 
but  the  toes  and  lingers  in  which  they  terminate  cooperate 
with  the  limbs  and  with  each  other  in  a  way  that  would  not 
be  possible  if  they  were  merely  finer  organs  of  movement 
separately  attached  to  the  body. 

Man  has  special  advantages  in  his  motor  endowment 
because  of  his  upright  position,  that  permits  the  effective 
use  of  the  hands,  because  of  the  llexibility  of  the  hands, 
and  the  possession  of  a  thumb  that  can  be  opposed  to  the 


32  GENETIC   PSYCHOLOGY 

fingers  in  manipulating  objects  and  handling  tools.  The 
motor  mechanisms  of  his  vocal  organs  and  of  his  eyes  are 
also  extraordinarily  versatile  and  delicate.  Without  such 
motor  structure  no  degree  of  sensory  refinement  would 
give  man  his  preeminence  above  other  animals. 

The  movements  that  are  most  frequently  useful  to  the 
species  are,  in  the  higher  animals  and  in  man,  provided 
for  by  the  arrangement  of  the  muscles  into  groups  that  are 
connected  with  bones  which  serve  as  levers,  in  such  a 
way  that  when  certain  muscles  begin  to  act,  other  mus- 
cles act  in  a  correlated  way,  and  a  movement  of  a  definite 
type  results  as  surely  as  the  pulling  of  one  rope  in  a  series 
of  pulleys  and  cords  causes  the  object  to  which  they  are 
attached  to  move  in  a  certain  direction.  The  extent  to 
which  movements  are  determined  by  the  arrangement  of 
muscle  groups  instead  of  by  nervous  connections  has  re- 
cently been  found  to  be  much  greater  than  was  formerly 
supposed.  It  is  possible  for  a  dog  with  a  nerve  cut,  which 
connects  a  limb  with  the  central  nervous  system,  to  use  the 
limb  fairly  well  in  walking.  Pressure  resulting  from  the 
weight  of  the  animal  and  the  consequent  movement  of 
some  muscles,  apparently,  in  such  cases  serve  as  a  stimu- 
lus to  the  moving  of  other  muscles. 

Man's  advantage  in  dealing  with  objects  arose  origi- 
nally from  the  high  development  of  a  motor  apparatus 
capable  of  a  variety  of  adjustments.  He  has. greatly  in- 
creased this  advantage  by  a  great  variety  of  tools  and  other 
mechanical  devices  for  moving  and  modifying  objects  with 
force,  quickness,  and  exactness. 

He  not  only  uses  tools  to  direct  and  increase  his  strength, 
speed,  and  effectiveness  in  moving  and  modifying  things. 


STRUCTURAL   BASIS   OF   BEHAVIOR  33 

liut  constructs  machines  to  utilize  and  direct  the  energy  of 
animals  and  of  wind  and  water.  He  does  not  stop  here,  but 
manufactures  power  through  the  transformation  of  one 
form  of  energy  into  another,  transports  it  and  directs  it  by 
means  of  machines  in  the  performance  of  all  kinds  of  acts. 
The  strength,  accuracy,  and  rapidity  of  motion  that  he 
can  control  is  therefore  almost  unlimited. 

SOMATIC   MOTOR    APPARATUS 

Not  all  motor  organs  are  concerned  in  obtaining  favor- 
able relations  with  the  environment.  A  vast  number  of 
small  and  less  conspicuous  organs  help  to  carry  on  the 
internal  activity  of  the  vital  organs.  They  also  transport 
to  every  portion  of  the  body  the  material  needed  to  continue 
its  activity  and  take  out  of  it  waste  materials.  Muscular 
tissue  is  found  not  only  in  the  heart,  lungs,  and  intestines, 
but  connected  with  every  blood  vessel  and  gland.  This 
system  of  motor  organs  is  in  general  separate  from  that 
concerned  in  relating  the  organism  to  its  environment. 

SPECIALIZATION   OF   CONNECTING   AND   REGULATING 
APPARATUS 

A  very  small  organism  in  direct  relation  with  its  environ- 
ment can  act  as  a  unit  without  any  special  connecting  and 
regulating  apparatus.  A  larger  animal  with  parts  well 
balanced  may  be  able  to  do  some  things  successfull}- 
without  a  close  organic  connection  between  parts.  The 
abdomen  of  a  bee  can  sting  as  effectively  when  properly 
stimulated  as  a  whole  bee,  but  the  animal  is  verv  much 


34 


GENETIC   PSYCHOLOGY 


crippled  if  one  wing  is  clipped.  Connection  between 
parts  is,  however,  of  advantage  even  in  the  lower  animals. 
One  arm  of  a  starfish  can  right  itself  when  severed  from 
the  body,  but  the  whole  animal  is  unable  to  right  itself  if 
the  nerve  ring  connecting  the  arms  is  severed,  because  each 
arm  then  acts  against  the  other  arms  instead  of  cooperating 
with  them  in  the  turning  movement. 

In  the  case  of  animals  that  react,  not  by  means  of  a 
special  apparatus  for  making  a  particular  kind  of  mo- 
tion, but  by  means  of  several  organs  combined  in  a  certain 
way,  connection  of  parts  is  absolutely  necessary.  Since 
in  such  animals  various  combinations  of  such  apparatus 
must  be  made  in  accomplishing  different  purposes,  an 
apparatus  that  not  only  gives  communication  of  one  part 
with  another,  but  also  helps  to  determine  what  particular 
combinations  to  make,  is  needed.  Such  an  apparatus 
will  be  more  useful  if  it  acts  differently  according  to  the 
results  of  previous  experience.  In  the  nervous  system  we 
have  an  apparatus  that  combines  these  qualities  in  a  high 
degree,  although  other  tissues,  especially  the  muscular, 
have  the  same  qualities  in  a  slight  degree. 

A  typical  nervous  apparatus  consists  of  a  sense  organ 
connected  by  a  sensory  nerve  with  a  center,  which  is  con- 
nected by  a  motor  nerve  with  a  motor  organ.  When  the 
sense  organ  is  stimulated,  the  impulse  passes  along  the  nerve 
fibers  to  the  sensory  cell  bodies,  and  through  the  dendritic 
processes  the  excitation  is  carried  to  the  motor  cell  bodies, 
and  an  impulse  passes  from  them  to  the  muscle,  causing 
it  to  contract.  Groups  of  such  cells  constitute  nerve 
centers.  In  the  higher  animals  there  arc  not  only  many 
such  groups  corresponding  to  different  parts  of  the  body, 


STRUCTURAL   BASIS   OF   BEHAVIOR  35 

but  as  we  shall  see  later  there  arc  often  several  centers  at 
different  levels  connected  with  the  same  parts  of  the  body 
by  means  of  which  one  part  is  adjusted  to  another. 

The  nervous  structure  is  remarkably  susceptible  to 
modification  and  very  retentive  of  such  modification. 
Hence  such  animals  as  possess  a  highly  developed  nervous 
system  are  able  in  a  way  to  carry  about  with  them  the  re- 
sults of  past  experience.  The  nervous  system  is  a  regula- 
tive apparatus,  at  least  in  the  sense  that  it  connects  parts 
more  effectively  than  other  tissues,  and  determines  what 
combinations  shall  be  made,  not  merely  by  reacting  more 
or  less  readily  than  formerly  to  certain  stimuli  being  re- 
ceived, but  by  acting  as  if  former  stimuli  were  now  pres- 
ent. In  other  words,  it  not  only  transmits  impulses  by 
means  of  which  the  proper  relation  of  })art  to  part  and  of 
the  whole  to  the  environment  is  maintained,  but  it  also 
serves  as  a  storage  house  of  experience  which  may  at  any 
time  largely  direct  the  reactions. 

In  large  animals  an  immense  number  of  strands  or 
nerve  fibers  are  needed  to  go  to  all  parts  of  the  skin,  to 
other  organs  of  special  sense,  to  the  vital  organs,  and  to  the 
muscular  apparatus.  The  natural  place  of  meeting  for  the 
fibers  carrying  these  stimulations  is  somewhere  inside  the 
body.  In  vertebrates  there  is  a  continuous  line  of  nervous 
tissue  near  the  center,  known  as  the  spinal  cord,  into  and 
from  which  the  nerve  fibers  run.  In  animals  below  the 
vertebrates  the  fibers  end  in  groups  of  nerve  cells  called 
ganglia,  sometimes  largely  isolated  from  ganglia  in  other 
parts  of  the  body,  and  sometimes  massed  into  what  is  called 
a  brain.  Usually  they  are  grouped  around  or  near  the 
mouth. 


36  GENETIC   PSYCHOLOGY 

These  central  masses  of  nerve  tissue  serve  as  means  of 
connecting  not  only  sense  organs  with  muscular  mechan- 
isms, but  each  sensory  apparatus  with  every  other,  and  less 
directly,  all  organs  and  tissues  with  them  and  with  each 
other.     In  the  higher  animals  there  is  a  very  large  mass  of 
nervous  matter  at  one  end  of  the  spinal  cord  which  con- 
stitutes the  brain.     In  fishes  the  brain  is  very  small,  and  it 
may  be  cut  away  without  greatly  affecting  their  movements. 
Frogs  live  for  a  considerable  time  after  its  removal,  and  can 
scarcely  be  distinguished  from  normal  animals,  except  that 
they   make   few   movements  when   not    stimulated,  and 
that  the  results  of  stimulation  can  be  more  accurately 
predicted.     A  brainless  frog  will  croak  with  almost  as 
much  certainty  when    stroked    in  a  certain  way  as  an 
electric  bell  will  ring  when  the  button  is  touched.     A  con- 
tinued stimulus,  however,  of  a  brainless  frog  may  result 
in  a  change  of  reaction,  just  as  we  shall  find  is  the  case  in 
some  of  the  animals  much  lower  in  the  scale  of  develop- 
ment.    For  example,  if  a  continued  acid  stimulus  is  ap- 
plied to  the  tlank  of  a  frog,  there  is  not  simply  a  movement 
of  contraction,  but  the  foot  moves  as  if  to  wipe  off  the  acid. 
If  it  cannot  do  so,  and  the  stimulus  continues,  the  other 
foot  may  be  used.     Similar  phenomena  of  the  spread  of  the 
effects  of  a  stimulus  to  organs  on  the  other  side  of  the  body, 
and  sometimes  to  all  parts  of  the  body,  have  been  found  in 
experiments  upon  the  nervous  system  of  other  animals. 

Pigeons  with  most  of  the  brain  removed  react  to  immedi- 
ate stimuli  in  much  the  same  way  as  ordinary  pigeons, 
but  they  do  not  usually  respond  to  suggestive  stimuli  in  a 
way  indicating  perception.  For  example,  they  respond  to 
contact  with  a  mate  in  much  the  same  way  that  they  would 


STRUCTURAL    BASIS   OF   BFJIAVIOR  37 

to  any  other  solid  object,  trying  to  get  over  it  or  around  it. 
Dogs  in  a  similar  condition  will  eat  food  placed  in  their 
mouths,  but  are  not  likely  to  take  it  in  response  to  a  visual 
stimulus.  It  appears,  therefore,  that  the  spinal  cord  of 
higher  animals  performs  much  the  same  function  as  the 
nervous  system  of  animals  lower  in  the  scale  and  without 
much  development  of  the  higher  sense  organs  of  sight 
and  touch. 

Besides  the  great  mass  of  nervous  tissue  in  the  spinal 
cord  and  brain  of  the  higher  animals,  which  is  concerned 
in  making  all  parts  work  together  in  responding  to  the 
environment  and  modifying  it  for  the  good  of  the  individual 
and  the  species,  there  is  a  large  amount  of  nervous  tissue 
forming  a  system  by  itself,  known  as  the  sympathetic 
nervous  system,  which  connects  all  the  internal  organs  in 
such  a  w^ay  that  they  can  act  harmoniously  and  effectively 
in  maintaining  life.  This  system  plays  the  same  part  in 
unifying  the  physiological  processes  that  is  played  by  the 
brain  and  spinal  cord,  or  central  nervous  system,  in  unify- 
ing the  behavior  of  an  organism  in  its  relation  to  its  en- 
vironment. The  two  systems  are,  however,  connected,  and 
the  activities  of  each  influence  the  other. 

REFERENCES 

*Angell.     Psychology,  Chapter  II. 

*Ayers,  E.  a.     Eyes  and  Vision  from  Worm   to   Man,  Harper's 

Monthly,  September,  1908. 
Baird,    J.   W.     The   Color   Sensitivity  of  the   Peripheral  Retina, 

Publications  of  the  Carnegie  Institution. 
*Carus.     The  Soul  of  Man,  pp.  66-106. 
♦Carpenter.     Mental  Physiology,  Chapter  II. 
*CoLE,  L.  J.    An  Experimental  Study  of  the  Image-Forming  Powers 


38  GENETIC  PSYCHOLOGY 

of  Various  Types  of    Eyes,  Proc.  Am.  Acad,    of  Arts  cf  Sci., 

1907,  pp.  335-417- 
Hall,  G.  S.  and  Donaldson,  H.  H.     Movement  Sensations  of  the 

Skin,  Mind,  Vol.  X,  pp.  557-572. 
J.A\rES.     Psychology,  Chapters  II,  III,  IV,  and  V. 
*JoRDAN  and  Kellogg.     Evolution  and  Animal  Life. 
*JuDD.     Psychology,  Chapters  II  and  V. 

Keller,  Helen.     Sense  and  Sensibility,  Century,  February,  1809. 
Kakuen,  G.  Hudson.     Speech  as  a  Factor  in  the  Diagnosis  and 

Prognosis  of  Backwardness  in  Children,  The  Training  School 

(Vineland,  N.J.),  April,  1908. 
KiRKPATRiCK.     Fundamentals  of  Child  Study,  Chapter  III. 
*Loeb,  J.     Comparative  Physiology  of  the  Brain  and  Comparative 

Psychology. 
♦Morgan,  C.  L.     Animal  Life  and  Intelligence,  Chapters  II,  VII. 
Nagel,  Dr.  Oskar.   On  Seeing  in  the  Dark,  Psych.  Rev.,  Vol.  XV, 

pp.  250-254. 
Parker,  G.  H.     The  Sense  of  Hearing  in  Fishes,  Am.  Nat.,  Vol. 

XXXVII,  p.  185. 
The  Skin  and  the  Eyes  as  Receptive  Organs  in  the  Reactions 

of  Frogs  to  Light,  Am.  Jr.  Physiol.,  Vol.  X,  p.  28. 
The  Function  of  the  Lateral  Line  Organs  in  Fishes,  Bull. 

Bureau  of  Fisheries ,  Vol.  XXIV,  p.  183. 
Hearing  and  Allied  Senses  in  Fishes,  Bull.  U.S.  Fish  Commis- 


sion for  1902,  pp.  45-62. 
*Washburn.     The  Animal  Mind,  Chapters  V,  VI,  VII. 
Yerkes,  R.  M.   The  Instincts,  Habits,  and  Reactions  of  the  Frog, 

Associative   Processes   of   the    Green    Frog,    Harvard  Psych. 

Studies,  Vol.  I,  p.  579. 
* The  Dancing  Mouse,  Chapters  III,  IV,  V,  VI,  VII,  VIII, 

IX,  X,  XL 


CHAPTER   III 


TYPES    OF   ANIMAL   BEHAVIOR 


AMCEBA 


The  amoeba  is  the  simplest  of  organisms,  without  organs 
or  distinct  parts,  and  with  no  permanent  form.  Its  be- 
havior is  similar  to 
that  of  inorganic 
semifluid  particles 
and  yet  is  distin- 
guished by  some 
of  the  fundamental 
characteristics  of  all 
organisms.  When 
floating  free  in  the 
water  it  has  no 
means  of  locomo- 
tion, but  it  can 
change     its    shape 

Fir,.  I.  —  Amoeba  proteus  suspended  in  the 
Dy  Senaing  out  -water,  showing  the  long  pseudopodia  extended  in 
pseudopodia  or  all  directions.  After  Leidy  (1879).  From  Jen- 
armlike  projections    "'"^^' 

in  every  direction.  This  is  likely  sooner  or  later  to  bring 
it  in  contact  with  food  particles  or  other  solids.  If  one 
pseudopodium  touches  a  solid,  it  remains  against  it,  and  the 
rest  flow  into  it,  and  then  the  whole  creature  in  its  new  form 

39 


40  GENETIC    PSYCHOLOGY 

can  move  along  the  surface  of  the  solid  by  a  sort  of  flowing 
movement,  by  which  the  upper  parts  flow  in  the  direction 
of  movement  over  the  lower.  Sometimes  several  pseu- 
dopodia  lead  the  advance,  but  none  form  in  the  rear.  Slight 
obstacles  modify  the  direction  of  movement  by  causing 
pseudopodia  to  project  out  to  one  side  into  which  the  rest 
of  the  creature  flows,  and  thus  it  gets  around  the  obstacle 
if  it  is  small.  If  the  obstacle  completely  bars  the  way, 
the  flowing  particles  reverse  their  direction,  and  the  creature 
moves  backward.     The  direction  of  movement  may  also 


a  t  c 

Fig.  2.  —  Method  by  which  a  floating   amoeba  passes  to  a  sohd.      From 
Jennings. 

be  modified  by  thermal,  chemical,  electrical,  and  light 
stimulations,  the  direction  of  movement  in  general  being 
away  from  injurious  stimuli. 

If  the  particle  touched  is  small,  the  amoeba  flows  around 
and  incloses  it,  and  if  it  is  a  food  particle,  digests  and  ab- 
sorbs it  into  itself.  If  the  particle  touched  rolls,  the 
amoeba  follows  and  begins  the  inclosure  again.  In  a  case 
observed  by  Jennings,  where  an  amoeba,  partially  inclosed 
by  another,  sent  out  pseudopodia  and  escaped,  the  larger 
amoeba,  which  had  started  to  move  away,  reversed  its 
movement  and  followed  and  caught  the  smaller  amoeba 
again,  a  movement  that  suggests  the  pursuit  and  capture 
of  prey  by  larger  animals.     On  the  other  hand,  if  we  sup- 


TYPES   OF   ANIMAL   BEHAVIOR 


41 


pose  that  there  is  a  certain 
amount  of  tension  in  the 
amoeba,  it  is  conceivable  that 
on  mechanical  principles  the 
movement  would  be  reversed 
when  the  tension  in  the  rear 
was  relieved  by  the  passing 
out  of  the  smaller  amoeba  at 
that  end. 

Although  subject  to  simple 
mechanical  and  physical  prin- 
ciples of  movement,  an  amoeba 


Fig.  4.  —  Negative  reaction  to  a  me- 
chanical stimulus  when  the  entire  an- 
terior end  is  strongly  stimulated,  a 
and  h,  successive  stages.  The  arrow  x 
shows  the  original  direction  of  motion; 
the  arrows  in  a  show  the  currents  im- 
mediately after  stimulation.  In  b  a 
new  tail  {t')  has  been  formed  from  the 
former  anterior  end,  uniting  with  the 
old  tail  (/).     From  Jennings. 


Fig.  3.  —  Negative  reaction  to  me- 
chanical stimulation  in  amoeba.  An 
amoeba  advancing  in  the  direction 
shown  by  the  arrows  is  stimulated 
with  the  tip  of  a  glass  rod  at  its  an- 
terior edge  (a).  Thereupon  this 
part  is  contracted,  the  currents  are 
changed,  and  a  new  pseudopodium 
sent  out  {b).     From  Jennings. 

is  a  particle  of  organized 
matter  that  tends  to  move 
because  of  energy  gener- 
ated within  itself,  though 
the  direction  of  its  move- 
ments is  changed  by  the 
various  stimuli  that  it  re- 
ceives. Its  movements  are 
also  in  general  of  such  a 
character  that  food  is  ob- 
tained and  injuries  avoided. 
In  this  it  resembles  higher 
animals,  and  also  in  the  fact 
that  it  responds  to  nearly  all 


42  GENETIC   PSYCHOLOGY 

the  principal  stimuli  that  they  do,  except  the  auditory.  It 
appears  also  that  its  movements  are  not  mechanically 
produced  from  without  but  from  within,  as  influenced  by 
previous  motion  and  the  effects  of  external  stimuli.  The 
migratory  cells  of  some  of  the  corpuscles  of  the  blood  of 
human  beings,  and  many  of  the  bacteria,  behave  in  a 
manner  very  much  the  same  as  the  amoeba.  Immunity 
to  disease  of  various  kinds  is  due  in  many  cases  to  increase 
in  number  of  those  cells  in  the  blood  that  feed  upon  and 
destroy  the  disease  germs.  If  such  cells  in  our  own  bodies 
are  organic  mechanisms  without  individual  consciousness, 
the  amoeba  and  other  lower  forms  of  animals  probably  are, 
while,  on  the  other  hand,  if  we  regard  the  amoeba  as  con- 
scious, we  should  think  of  many  of  the  cells  of  our  own 
body  and  the  swimming  spores  of  plants  as  having  each  a 
consciousness  of  its  own. 

Even  if  it  is  admitted  that  the  amoeba  is  conscious,  its 
responses  to  mechanical,  chemical,  electrical,  thermal,  and 
light  stimulation,  do  not  necessarily  imply  definite  sensa- 
tions of  contact,  heat,  taste,  smell,  or  sight.  There  is  little 
or  no  differentiation  in  its  reactions  to  these  various  stimuli, 
but  merely  positive  or  negative  reaction  according  as  the 
stimulus  of  whatever  kind  is  favorable  or  unfavorable. 
So  long  as  the  response  of  any  animal  to  a  stimulus  is  not 
specifically  different  from  the  response  to  other  stimuli, 
there  is  no  more  reason  to  suppose  differentiated  sensations 
for  each  stimulus  than  there  is  to  suppose  that  a  person 
who  responds  to  sounds  of  all  degrees  of  pitch,  or  light  of 
all  colors,  necessarily  discriminates  each  from  all  others. 
On  the  other  hand,  failure  to  respond  to  any  stimulus 
does  not  positively  prove  that  it  produces  no  effect,  for 


TYPES    OF   ANIMAL   BEHAVIOR 


43 


stimuli  that  have  no  practical  significance  to  animals  may 
be  ignored  by  them  as  they  often  are  by  man. 


INFUSORIA 

These  are  more 
completely  organized 
than  the  amoeba,  with 
more  permanency  of 
form  and  specializa- 
tion of  parts.  The 
surface  or  ectosarc  is 
thicker  and  less  flex- 
ible than  that  of  the 
amoeba,  so  that  pseu- 
dopodia  cannot  be 
sent  out  or  food  in- 
closed by  all  portions 
of  the  body.  There 
is  an  opening  for 
taking  in  the  food, 
known  as  the  oral 
cavity  or  mouth,  and 
another  for  excretion. 
Movements  are  made 
chiefly  by  means    of 

cilia,    though    the    be-       p,^    ^_  _  p.^amedum,  viewed  from  the  oral 
ginningS    of    contract-    surface.     Z.,  left  side;  i?,  right  side;  o?«.,  anus; 

ile  or  muscular  tissue  "''  "''°'^|'"=  '""  ^"dosarc;  /.v.,  food  vacu- 

oles;  g,  gullet;  w,  mouth;  wa.,  macronucleus; 
can  be  detected  in  mi.,  micron ucleus;  o.g.,  oral  groove;  p.,  pel- 
these   creatures.  '''^'^'  ''"'  trychocyst  layer.     The  arrows  show 

,_,  .  the  direction  of  movement  of  the  food  vacuoles. 

The       Paramecium,    From  Jennings. 


44 


GENETIC   PSYCHOLOGY 


often  visible  to  the  naked  eye  in  fresh  water  among  de- 
caying vegetation,  is  typical  in  its  behavior.  It  is  cigar- 
shaped,  with  the  mouth  nearer  the  pointed  end,  which 
enables  us  to  use  the  term  "anterior"  for  that  end  and 
"posterior"  for  the  other  end.  The  surface  opposite  the 
mouth  may  be  called  the  aboral  surface  (back)  of  the  ani- 
mal. Viewed  in  this  way  the  animal  has  not  two  similar 
sides  but  is  slightly  spiral  in  form.     The  path  of  the  animal 


/.  ^- 

FiG.  6.  —  Diagram  of  the  avoiding  reaction  of  Paramecium.  A  is  a  solid 
object  or  other  source  of  stimulation.  i-6,  successive  positions  occupied  by 
the  animal.     (The  rotation  on  the  long  a.xis  is  not  shown.)     From  Jennings. 

in  swimming  is  spiral  because  the  cilia  strike  in  a  slightly 
oblique  direction  and  because  the  oral  ones  strike  more 
vigorously  than  the  others.  In  backward  movement  the 
cilia  simply  reverse,  and  the  path  is  still  spiral,  the  direction 
changing  as  the  oral  or  mouth  portion  is  up  or  down. 
Since  there  is  continual  rotation,  the  general  direction  of 
the  spiral  may  be  maintained. 

Its  characteristic  avoiding  movement  when  it  strikes  a 
solid  is  to  reverse  cilia,  move  backward,  turn  to  one  side, 
and  move  forward  again.     This  movement,  repeated  if 


TYPES    OF   ANIMAL    BEHAVIOR 


necessary,  usually  gets  it  away  from 
or  around  an  obstacle.  The  more 
rapid  movement  of  the  cilia  next 
the  mouth  causes  a  current  down 
the  mouth  that  brings  food  and  also 
gives  the  animal  samples  of  the 
liquid  from  various  directions,  thus 
offering  a  chance  for  reaction  to 
chemical  or  other  stimulation  before 
the  creature  has  actually  entered  the 
medium  containing  it. 

If  it  approaches  water  that  is  hot, 
the  cilia  reverse,  causing  the  animal 
to  move  backward ;  then  they  act 
directly  again,  and  the  animal  is 
turned  partly  over  and  moves  for- 
ward in  a  new  direction.  If  the 
unfavorable  medium  is  not  thus 
avoided,  the  action  is  repeated  again 
and  again,  till,  if  possible,  a  favor- 
able direction  of  movement  is  found. 
In  the  presence  of  chemical  and 
thermal  stimuli  the  front  sometimes 
swings  around  until  the  unfavorable 
stimulus  is  not  received,  then  the 
forward     movement     takes     place. 


Fig.  7.  —  Spi- 
ral path  of  Par- 
amecium. The 
figures  I,  2,  3,  4, 
etc.,  show  the 
successive    posi- 


This  movement  is  quite  analogous  tions    occupied. 

.         .1      ,         r                                                •        1  The  dotted  areas 

to    that    01     a    person    or    animal  ...         „ 

i  with    small     ar- 

when  he  looks  around  before  mov-  rows   show  the 

ing  in  what  seems  to  be  the  most  ^""^"^^  ^"^  ^^^^^  ^™ 

from  in  front.     From  Jen- 

favorable  direction,  except  that  the  nings. 


46 


GENETIC   PSYCHOLOGY 


injurious  stimulus  is  actually  present    instead    of   being 
suggested  by  another  stimulus. 

If  it  is  dropped  into  water  slightly  hotter  than  it  is 
used  to,  it  makes  the  avoiding  reaction  once  or  twice,  then 


a 

;'  ^  >  ;  '/' '_ :  '-.'■/'w'-'  ,'/',--/:■/: ;.-  --;  ;-I 

19-                                                      19' 

l 

L|ir-£-.-I%5£->i :-:  =  .-■-;  '.-'.'■' 

26-                  ""■                                 38- 

c 

IH 

10' 


25- 


Fig.  8.  —  Reactions  of  paramecia  to  heat  and  cold,  after  Mendelssohn 
(1902).  At  a  the  infusoria  are  placed  in  a  trough,  both  ends  of  which  have 
a  temperature  of  19  degrees  C.  They  are  equally  scattered.  At  h  the  tem- 
perature of  one  end  is  raised  to  38  degrees,  while  the  other  is  only  26  degrees. 
The  infusoria  collect  at  the  end  having  the  lower  temperature.  At  c  one  end 
has  a  temperature  of  25  degrees,  while  the  other  is  lowered  to  10  degrees. 
The  animals  now  collect  at  the  end  having  the  higher  temperature.  From 
Jennings. 

ceases,  the  change,  not  the  absolute  temperature,  evi- 
dently being  reacted  to.  If  the  water  is  very  hot,  it  con- 
tinues the  alternate  reversal  and  forward  movements 
until  it  dies. 

The  turning  is  always  toward  the  aboral  side,  and  this 
helps  to  avoid  injurious  media,  when,  as  usual,  they  affect 


TYPES   OF   ANIMAL   BEHAVIOR 


47 


the  mouth  first;  but  if  experimentally  the  stimulus  is  given 
on  the  aboral  side,  the  turning  is  toward  instead  of  away 
from  the  stimulus,  and  the  injurious  medium  is  entered 
instead  of  being  avoided.  Thus  the  movements  that  under 
the  ordinary  conditions  of  its  life  are  helpful  are,  under 
unusual  conditions,  harmful. 

Seemingly  positive  reactions  are  often  really  negative, 
as  when  animals  in  a  half  per  cent  salt  solution  gather  in 
a  drop  of  one  tenth  per  cent  solution.  This  is  because 
they  accidentally  get 
in  the  weaker  solu- 
tion as  they  move 
in  various  directions 
and  react  by  rever- 
sal whenever  they 
touch  the  stronger 
and  less  favorable 
solution.  In  a  simi- 
lar way  they  gather  where  light  and  temperature  are 
least  unfavorable,  the  avoiding  reaction  occurring  only 
when  they  pass  away  from  the  optimum.  If  a  weak  acid 
instead  of  a  salt  solution  is  placed  in  the  water,  the  para- 
mecia  collect  in  it  for  the  same  reason.  The  animals 
themselves  give  off  carbonic  acid,  which  is  favorable,  hence 
they  are  likely  to  gather  in  groups  because  movement 
into  pure  water  produces  the  avoiding  reaction. 

Experiment  shows  that  the  avoiding  reaction  is  not  pro- 
portional to  the  osmatic  pressure  or  to  the  strength  of 
injurious  substances,  some  solutions  producing  avoiding 
reactions  only  at  the  killing  strength  and  others  at  a  small 
fraction  of  the  killing  strength.     Paramecia  pass  into  all 


Fig.  g.  —  Collection  of  paramecia  in  a  drop 
of  bV  per  cent  acetic  acid.     From  Jennings. 


48  GENETIC    PSYCHOLOGY 

acid  solutions  without  the  avoiding  reaction,  but  give  it 
upon  starting  out,  hence  they  remain,  although  in  some 
cases  death  is  the  result.  This  is  another  illustration  of 
behavior  determined  in  a  certain  environment  by  natural 
selection;  for  the  substances  not  reacted  to  until  of  killing 
strength  are  not  usually  found  in  the  medium  in  which 
the  Paramecium  lives. 

When  the  paramecium  is  moving  slowly  and  strikes 
lightly  against  a  solid,  it  may  move  backward  a  short  dis- 
tance, then  forward  again,  and  come  to  rest  against  the 
solid.  In  this  case  the  cilia  against  the  solid  become 
still  and  those  of  the  posterior  end  may  either  move  or 
become  quiet ;  but  those  next  the  mouth  continue  to  move, 
which  often  results  in  food  being  drawn  into  the  mouth 
from  decaying  vegetation,  against  which  the  animal  is  in 
such  cases  likely  to  be  resting. 

In  swimming,  paramecia  are  likely  to  move  in  a  direc- 
tion opposed  to  gravity  until  they  are  near  the  surface. 
When  resting  against  a  solid,  the  anterior  end  may  point 
in  any  direction,  but  is  rather  more  likely  to  point  upward, 
perhaps  because  of  the  different  specific  gravity  of  the 
substance  of  which  the  animal  is  composed.  Slight  local 
contractions  of  the  ectosarc  occur  in  response  to  various 
stimuli,  though  no  muscular  substance  has  been  discovered 
in  it. 

Experiment  shows  that  the  animal  responds  more  readily 
to  mechanical  stimuli  on  the  anterior  end  than  on  the 
posterior,  hence  there  is  some  differentiation  of  the 
surface  into  more  and  less  sensitive  portions.  This  may 
be  looked  upon  as  the  beginning  of  surface  dift'erentiation 
upon  which  proper  space  reactions  and  space  perceptions 


OF 
TYPES   OF   ANIMAL   BEHAVIOR  49 

depend.  A  jar  is  reacted  to  by  an  avoiding  movement 
just  as  if  the  more  sensitive  anterior  end  had  been  stimu- 
lated, hence  local  signs  or  differentiation  of  surface  are 
evidently  the  determining  factor  in  space  reaction. 

When  two  stimuli  are  acting  at  once,  paramecia  show 
more  variability  in  reacting,  thus  one  receiving  the  contact 
stimulus  does  not  respond  so  readily  to  heat,  mechanical, 
or  chemical  stimulation  as  one  that  is  swimming ;  while 
on  the  other  hand,  strong  thermal  stimulation  modifies 
the  contact  reactions.  Again,  electrical  stimulation  modi- 
fies reaction  to  heat  and  chemicals.  A  paramecium 
that  is  feeding  does  not  respond  so  readily  to  stimula- 
tions. This  is  analogous  to  the  behavior  of  higher  organ- 
isms that  are  said  to  be  ignoring  one  stimulus  because 
they  are  attending  to  another. 

Internal  conditions,  due  to  previous  stimulations  or 
movements  or  to  nutritive  conditions,  greatly  modify 
behavior.  A  paramecium  that  has  recently  fed  and  is  in 
a  favorable  medium,  usually  remains  quiet  if  not  disturbed, 
and  if  stimulated,  does  not  respond  c^uite  so  readily  as 
usual,  while  one  that  has  not  fed  for  some  time  is  likely 
to  move  around  a  great  deal.  Unfavorable  stimulation 
also  causes  great  activity.  This  illustrates  the  general 
truth  that  all  organisms,  including  man,  do  more  and  de- 
velop more  when  the  conditions  of  life  are  not  all  favorable. 

From  a  study  of  paramecia  it  appears  that  seemingly 
positive  movements  in  search  of  favorable  stimuli  are  often 
due  to  hunger  or  unfavorable  conditions  produced  by  an 
injurious  medium,  that  these  movements  are  as  likely  to 
be  away  from  as  toward  favorable  conditions,  and  that 
favorable  conditions  are  obtained  chiefly  through  negative 


50  GENETIC   PSYCHOLOGY 

reactions  to  all  unfavorable  stimuli  that  arc  received,  and 
continued  positive  movements,  until  the  creature  is  again 
in  harmony  with  its  environment.  Positive  reactions  to 
favorable  stimuli,  therefore,  first  appear  chiefly  in  the  form 
of  a  slowing  of  movement  or  its  cessation  when  a  favorable 
stimulus  is  received.  There  is  no  reaction,  either  negative 
oi  positive,  to  a  stimulus  not  touching  the  animal,  though 
there  is  reaction  in  some  cases  before  any  part  but  the 
mouth  has  been  stimulated.  The  paramecium  differs 
from  the  amoeba  chiefly  in  having  a  better  developed  and 
more  permanent  apparatus  for  making  preservative  move- 
ments. It  is  indeed  a  wonderful  illustration  of  how  many 
and  how  varied  movements,  that  are  generally  useful, 
can  be  made  by  means  of  the  same  simple  apparatus. 

In  taking  food,  the  method  of  trial  and  varied  action  is 
used  by  the  paramecium,  everything  being  taken  that  can 
be,  the  larger  and  harder  particles  being  rejected  by  an 
avoiding  movement,  while  digestible  substances  are  ab- 
sorbed and  smaller  useless  particles  are  passed  on  and 
eliminated.  No  discrimination  is  shown  in  taking  food, 
but  different  objects  produce  different  movements  after 
they  are  taken. 

That  movement  depends  on  internal  conditions  as 
affected  by  previous  stimulations,  is  shown  very  clearly 
by  the  behavior  of  stenlor,  another  variety  of  infusoria 
with  greater  possibilities  of  varied  movement  than  the 
Paramecium.  These  creatures  are  usually  attached  to 
some  surface  by  a  tube  into  which  they  can  contract. 
If  stimulated  by  a  jet  of  water  that  is  not  harmful,  they 
contract,  then  after  they  have  resumed  a  normal  position, 
a  similar  jet  of  water  is  not  responded  to,  the  animal  ap- 


TYPES    OF   ANIMAL   BEHAVIOR 


51 


parently  having  become  used  to  this  new  form  of  harmless 
stimulation,  just  as  higher  animals  become  used  to  a  sound 
that  is  repeated  several  times  in  succession.     If  the  stimu- 


FiG.   10.  —  Stentor  roeselii,  showing  the  currents  caused  bj' the  cilia  of  the 
peristome.     From  Jennings. 

lus  is  given  more  strongly ,  there  maybe  several  contractions, 
or  the  body  may  bend  to  one  side  as  if  to  avoid  the  stimulus 
in  that  way. 
When  an  injurious  stimulus  is  given,  the  first  avoiding 


52  GENETIC   PSYCHOLOGY 

reaction  is  usually  that  of  bending  first  to  one  side  and 
then  to  the  other,  which,  if  not  successful,  is  followed  by 
contracting  into  the  tube.  If  the  stimulus  still  continues, 
it  contracts  violently  in  its  tube  till  it  breaks  its  attachment, 
when  it  swims  away  from  the  irritating  stimulus.  It  then 
moves  around  as  if  searching  for  a  suitable  place,  and  after 
finding  it,  oscilates  over  it  in  a  way  that  hastens  the  forma- 
tion of  mucus,  by  which  it  soon  becomes  attached.  Such 
behavior  is,  on  the  one  hand,  suggestive  of  consciousness, 
while  on  the  other  it  is  very  analogous  to 
phenomena  found  by  physiologists  in 
studying  the  effects  of  repeated  stimu- 
lation of  a  nerve  and  muscle  that  have 
been  dissected  out  for  experimental  pur- 
poses, also  similar  to  the  movements  of 
a  headless  frog.     Summation  of  stimuli 

Fig.     II.  — ■  Stentor  ,-,.„.  . 

roeseiii  contracted  into  ^nd  diffusion  to  Other  parts,  causmg  new 
its  tube.  From  Jen-  and  Varied  movements  as  in  the  stentor, 
^^^^'  are  common  in  all  animal  mechanisms. 

The  resulting  movements  are  like  the  trial  and  success  move- 
ments of  the  Paramecium,  only  in  a  greater  variety  made 
possible  by  more  complex  motor  apparatus.  The  changes 
in  behavior  must  be  due  to  changes  within  the  creature, 
since  the  stimulus  and  other  external  conditions  remain 
the  same.  The  action  seems  to  be  self-preservative  or 
regulatory,  like  learning  by  experience  in  higher  animals ; 
but  the  m^odification  is  temporary,  perhaps  lasting  no 
longer  than  the  condition  immediately  produced  by  the 
stimulus. 

However  crude  and  wasteful  these  methods  of  maintain- 
ing life  may  be,  they  are  not  to  be  confused  with  the  chance 


TYPES   OF   ANIMAL    BEHAVIOR 


53 


movements  of  an  inorganic  body  affected  by  wind,  wave, 
or  other  force,  for  the  organism  is  not  moved  by  the 
stimulus  but  moves  itself  in  response  to  it.  The  move- 
ments are  also  regulatory,  since  if  they  are  not  at  once 
successful,  they  continue  and  vary  until  relief  is  obtained. 


Fig.  12.  —  Spontaneous  changes  of  positions  in  an  undisturbed  hj-dra. 
Side  view.  The  extended  animal  (i),  contracts  (2),  bends  to  a  new  position 
(5),  and  then  extends  (4).    From  Jennings. 


LOWER    FORMS    OF    METAZOA  —  HYDRA,  MEDUSA 

Types  of  the  lower  forms  of  the  mctazoa  are  the  hydra 
and  medusa.  The  hydra  has  nerve  cells  with  branching 
processes  scattered  through  the  body,  evidently  performing 
the  usual  function  of  nervous  structure,  that  of  connecting 
parts  with  each  other. 


54 


GENETIC   PSYCHOLOGY 


Under  the  same  conditions  a  hydra  that  has  been  without 
food  for  some  time  is  more  active  than  one  that  has  had 


Fig.  13.  —  Hydra  looping  along  like  a  leech.     After  Wagner  (1905).     1-6, 
successive  positions.     From  Jennings. 

enough.     Any  movement  is  hkely  to  bring  it  sooner  or 
later  into  contact  with  food,  hence  is  advantageous. 

The  more  usual  position  of  the  hydra  is  with  foot  at- 
tached and  head  free.  Gravity  does  not  seem  to  determine 
the  position,  for  if  there  is  a  solid  above  to  which  the  foot 


TYPES   OF  ANIMAL   BEHAVIOR 


55 


may  be  attached,  the  animal  hangs  with  head  down  and 
of  course  free.  Some  relatives  of  the  hydra  seem  very 
responsive  to  gravity. 

Under  the  stimulus  of  hunger  or  unfavorable  stimulus 
the  head  of  the  hydra  bends  over  and  becomes  attached 
and  the  foot  straightens  up,  thus  producing  inversion. 


Fig.  14.  —  A  chemical  {ch)  is  brought  against  a  certain  spot  on  one  side  of 
a  Hydra  {a).  Thereupon  this  spot  contracts,  bending  the  Hydra  toward  the 
side  stimulated  (6).     From  Jennings. 

This  is  followed  by  bending  to  attach  the  foot,  the  raising 
of  the  head,  and  the  righting  movement.  By  such  motions 
the  animal  continues  to  change  his  position  till  relief  is 
obtained. 

As  a  rule,  movements  in  response  to  unfavorable  stimu- 
lation are  sooner  or  later  such  as  result  in  relief,  yet  if  the 
whole  animal  is  thrown  into  hot  water,  they  continue, 
though  nothing  is  gained.  The  mechanical  character  of 
the  movements  is  still  further  indicated  by  the  fact  that  if 
the  foot  instead  of  the  head  is  stimulated,  the  movement 
of  contraction  is  the  same  and  thus  the  stimulus  is  ap- 


56  GENETIC    PSYCHOLOGY 

preached  instead  of  receded  from.  This  is  of  course  only 
another  illustration  of  natural  selection  fixing  a  movement 
that  is  under  usual  conditions  beneficial,  so  that  it  will  be 
made,  whether  in  the  particular  case  it  is  beneficial  or 
harmful. 

Local  stimuli  sometimes  produce  local  reactions  only. 
Thus  if  a  hydra  is  stimulated  lightly  on  the  side,  the  por- 
tion affected  contracts,  and  as  a  result  the  animal  bends 
over. 

Hydrae  gather  on  the  moderately  lighted  side  of  a  vessel 
rather  than  on  the  dark  side.  Food  is  more  often  found 
on  that  side,  so  the  gathering  on  that  side  may  be  partly 
due  to  the  greater  activity  when  hungry  and  less  activity 
when  there  is  plenty  of  food.  Hydrae  gather  where  there 
is  oxygen,  which  is  usually  at  the  surface,  probably  because 
of  negative  reactions  when  they  start  to  leave  the  region 
of  oxygen. 

Unless  very  hungry  the  food-taking  reaction  is  not  called 
forth  by  mechanical  stimuli  alone  as  in  paramecia,  and 
not  usually  by  chemical  stimuli  only,  meat  juice  alone  not 
producing  it  unless  the  animal  is  very  hungry.  Both  kinds 
of  stimuli  are  usually  necessary,  hence  we  have  what 
amounts  to  a  partial  selection  of  food,  everything  not 
being  swallowed  as  it  is  by  the  paramecium,  but  only  such 
particles  as  give  both  contact  and  chemical  stimulation. 

In  the  medusa  the  nervous  and  contractile  tissue  is 
better  developed  than  in  the  hydra,  with  the  nervous  tissue 
arranged  in  two  rings  and  connected  with  the  contractile 
tissue.  This  improved  structure  makes  possible  a  more 
effective  form  of  reaction  than  that  of  trial  movements. 
In  the  medusa  the  first  contraction  often  helps  to  move 


TYPES   OF   ANIMAL   BEHAVIOR  57 

the  part  stimulated  and  the  whole  animal  away  from  the 
stimulus.  Such  movements  are  the  forerunners  of  reflexes 
and  instincts  that  become  more  definite  with  elaboration 
of  mechanisms  for  producing  them  so  that  they  are  im- 
mediately protective  and  not  merely  advantageous  by 
varied  action  and  final  success.  The  hydra,  as  we  have 
seen,  changes  its  position  when  intensely  stimulated,  but 
is  as  likely  to  move  toward  the  stimulus  as  away  from  it. 

The  medusa  is  said  to  "fish"  with  its  tentacles,  and  it  is 
more  active  when  food  is  near  if  it  has  not  just  fed,  but  the 
food  is  found  by  trial  and  error  rather  than  by  direct 
approach.  After  the  food  has  been  touched,  the  whole 
body  works  together  to  secure  and  swallow  it.  Mild 
food-securing  reactions  may  be  called  forth  by  experimental 
use  of  mechanical  and  chemical  stimuli  that  have  no  food 
value,  but  they  soon  cease  when  the  usual  series  of  food- 
securing  stimuli  are  not  received.  Contact  with  a  moving 
and  struggling  object  causes  the  food  reaction  to  be  made 
and  completed,  while  contact  with  a  motionless  object 
does  not  produce  the  reaction  at  all.  This  is  a  further 
basis  of  food  selection,  since  living,  moving  objects  are  the 
usual  food. 

The  mechanical  nature  of  the  food-taking  reaction  of 
the  medusa  is  strongly  suggested  by  experiments  in  which 
one  tentacle  with  its  base  is  separated  from  the  others,  and 
when  stimulated  with  food,  bends  in  the  same  direction 
it  would  have  bent  had  it  been  still  a  part  of  the  whole 
animal.  When  such  a  mechanism  is  a  part  of  the  whole 
body,  it  may  be  made  active  by  the  movement  of  an  adja- 
cent part  in  response  to  a  stimulus  and  its  own  activity 
may  be  either  greater  or  less  because  of  what  is  taking 


58  GENETIC   PSYCHOLOGY 

place  in  adjacent  mechanisms.  This  is  typical  of  what 
takes  place  in  reactions  of  higher  animals,  except  in  them 
the  relation  of  part  to  part  is,  as  we  shall  see,  much  closer. 
Thus  not  simply  the  part  stimulated,  but  the  whole  body 
is  modified  by,  and  reacts  in  response  to,  a  local  stimulus. 
The  connection  of  parts  is  closer  because  of  a  more  com- 
plete and  developed  nervous  system  that  greatly  facilitates 
transmission  of  stimuli  as  well  as  contractile  effects. 


STARFISH 

The  echinoderm  family  is  best  represented  by  the  star- 
fish. The  general  form  of  the  starfish  is  suggested  by  its 
name.  Attention,  however,  should  be  called  to  the  fact 
that  besides  the  five  movable  arms  with  secondary  motor 
organs  in  the  form  of  tube  feet,  there  are  a  vast  number 
of  little  organs  known  as  pedicellariae  all  over  the  surface 
of  the  body  that  serve  the  purpose  of  protecting  the  many 
little  openings  that  serve  as  gills  and  also  for  capturing 
prey.  These  little  organs  rise  up  above  the  spines  and  open 
their  jaws  whenever  the  gills  are  stimulated  by  a  small 
moving  object  and  close  upon  whatever  is  then  in  contact 
with  them.  The  delicate  gills  are  thus  protected  and 
various  animals  captured  for  food.  The  stimulus  that 
causes  one  or  more  pedicellarise  to  rise,  spreads  without 
nervous  connection  and  causes  others  to  rise.  Those 
that  have  recently  been  stimulated  are  most  sensitive, 
as  is  shown  in  a  striking  way  by  the  fact  that  pedicellariae 
that  have  been  recently  stimulated  may  rise  when  others 
at  some  distance  do  so,  although  the  intervening  pedicel- 
larise do  not.     These  facts  indicate  that  although  nervous 


TYPES   OF   ANIMAL   BEHAVIOR  59 

tissue  is  especially  suited  to  the  transmission  of  excitation, 
yet  other  tissue  can  perform  that  function. 

In  general  the  starfish  moves  away  from  light,  but  it 
seems  to  have  some  sort  of  rudimentary  sense  of  sight 
that  causes  it  to  move  toward  objects  when  not  in  their 
shadow  even  when  it  must  pass  through  a  slightly  brighter 
space  to  do  so.  It  reacts  as  a  whole  to  tactual  and  other 
stimuli  in  such  a  way  as  to  get  away  from  unfavorable 
stimuli  and  secure  favorable  ones.  The  stimulus  given 
by  a  moving  object  may  result  in  its  seizure,  but  unless  a 
chemical  stimulus  is  also  given  the  movement  of  bringing 
the  object  to  the  mouth  is  not  produced.  As  a  result,  it 
rarely  swallows  any  but  living  objects. 

The  behavior  of  starfish  in  righting  themselves  when 
turned  over  has  been  most  studied.  All  the  arms  are 
likely  to  begin  to  be  more  or  less  active,  but  as  soon  as  one 
or  two  have  become  attached  to  some  object  the  others 
join  in  a  unified  impulse  by  folding  under  and  turning 
the  whole  body  over. 

A  particular  specimen,  studied  by  Jennings,  used  certain 
arms  for  righting  itself  more  than  others,  while  one  arm 
was  not  used  at  all.  The  attempt  was  made  to  induce  the 
animal  to  use  this  arm  by  preventing  it  from  turning  over 
unless  it  did.  The  attempt  was  successful,  and  further 
practice  was  given  in  the  use  of  that  arm  until  it  was  readily 
used.  The  creature  was  then  placed  on  its  back  and  al- 
lowed to  right  itself  without  interference  and  was  found  to 
use  the  formerly  unused  arm  much  of  the  time  even  after 
an  interval  of  two  days. 

Here  we  evidently  have  an  instance  of  behavior  in  an 
individual  organism,  modified  by  the  results  of  previous 


6o  GENETIC   PSYCHOLOGY 

activity,  in  a  manner  very  analogous  to  what  in  higher 
creatures  we  call  memory.  In  the  organisms  previously 
studied  we  have  noted  changes  in  behavior  due  to  the  per- 
sisting effect  of  recent  stimulation  and  movement,  but  here 
we  have  something  more.  It  is  not  simply  the  immediate 
after  effects  that  remain,  but  a  more  persisting  modification 
of  the  organism. 

The  change  in  habit  in  the  case  of  the  starfish  disappears 
rather  rapidly  if  it  is  allowed  to  right  itself  under  various 
conditions,  because  the  direction  of  righting  is  influenced 
by  the  direction  of  the  light,  the  position  of  the  body,  the 
kind  of  surface  with  which  the  several  arms  first  come  in 
contact  and  also  by  previous  movements  and  various  other 
external  and  internal  factors.  The  repetition  of  any  factor 
that  proves  to  be  dominant  may  therefore  start  a  new  habit 
that  will  soon  be  as  strong  as  the  one  given  the  animal  by 
special  training. 

MOLLUSCA 

In  these  creatures,  of  which  the  clam  is  the  most  gener- 
ally known,  sense  organs  are  not  highly  developed,  but  some 
portions  of  the  body  are  more  sensitive  to  light  than  other 
portions.  Their  reactions  to  light  are  not  due  chiefly  to 
the  immediately  harmful  or  favorable  effects  of  light 
stimulation,  but  to  the  usual  significance  of  the  variations 
in  the  light  stimulus.  For  example,  clams  close  their 
shells  in  response  to  the  shadow  of  a  moving  object,  not 
because  the  shadow  is  injurious,  but  because  it  is  the  pre- 
cursor of  a  possible  enemy.  Nearly  all  the  reactions  of 
these  and  higher  animals  to  light  are  due  not  to  the  immedi- 
ate physiological  effects  of  the  light  stimulation  but  to  the 


TYPES    OF   ANIMAL   BEHAVIOR  6l 

relation  of  light  variations  to  helpful  or  harmful  objects 
in  the  surroundings.  Bohn  has  shown  that  the  movements 
of  littorinas  nidis,  a  species  of  periwinkle,  may  be  directed 
at  will  by  means  of  light  and  dark  screens  of  various  sizes 
placed  in  appropriate  positions,  the  direction  of  movement 
of  the  animal  being  the  result  of  the  positive  and  negative 
effects  of  light  upon  it.  The  shadows  of  rocks  and  other 
objects  in  its  natural  environment  probably  serve  as 
directors  of  its  movements  in  searching  for  food. 

In  this,  as  in  other  cases,  there  is  no  permanent  and  un- 
changing mode  of  reaction  to  light  stimulation,  but  the 
reaction  is  influenced  by  various  causes  internal  and  ex- 
ternal, connected  with  the  usual  conditions  of  life.  This  is 
well  illustrated  by  the  reactions  of  different  varieties  of  the 
littorina  living  at  different  elevations  among  the  rocks 
washed  by  the  tide.  When  the  tide  is  out  they  move  over 
the  rocks  in  search  of  food,  those  at  a  higher  level  moving 
toward  the  water  and  those  at  a  lower  level  away  from  it 
toward  the  rocks,  the  movement  in  one  case  being  aw^ay 
from  the  shadow  of  the  rock,  and  in  the  other  case  toward 
it.  Those  at  the  middle  level  show  more  marked  varia- 
tions in  their  positive  and  negative  reactions  correspond- 
ing to  the  position  of  the  sun  and  the  coming  in  and  going 
out  of  the  tide.  These  movements  are  not,  however,  de- 
termined wholly  by  the  immediate  stimulus  of  variations  in 
light  and  in  moisture,  but  are  to  some  extent  the  result  of 
rhythmic  changes  in  the  organisms  which  render  them  at 
one  time  positively  j)hototactic  and  at  another  time  nega- 
tively phototactic.  This  was  demonstrated  upon  specimens 
of  these  animals  in  an  aquarium  by  means  of  experiments 
with  light  and  dark  screens  at  different  times  of  the  day. 


62  GENETIC   PSYCHOLOGY 

Bohn  proved  that  other  sea  creatures  have  a  rhythm  estab- 
lished in  their  organism  by  the  tides.  A  sea  anemone  that 
Uves  attached  to  stones  in  pools  closes  when  the  tide  is  low 
and  oxygen  becomes  scarce  and  opens  when  the  waves  of 
the  high  tide  strike  it.  Artificially  produced  waves  in  an 
aquarium  call  forth  the  reaction  at  the  time  of  high  tide 
but  not  at  other  times.  Individuals  that  have  lived  in 
deep  water  so  that  they  were  not  exposed  at  low  tide,  do  not 
react  in  this  way. 

CRUSTACEA 

In  Crustacea,  of  which  crabs  and  lobsters  are  the  most 
familiar  examples,  there  are  clearly  developed  organs  of 
sight  and  the  reactions  of  these  creatures  to  light  are  de- 
termined, not  by  its  effect  upon  the  body  as  a  whole,  but 
upon  the  amount  and  portion  of  the  eye  surface  that  is 
illuminatedo  Their  reactions  to  light  stimulations,  as 
determined  by  surrounding  objects,  are  much  more  com- 
plex than  in  the  case  of  mollusca.  Since  they  react  to 
numerous  objects,  favorable  and  unfavorable,  in  various 
ways,  it  follows  that  the  explanation  of  their  reactions 
cannot  be  found  in  .the  mere  physical  fact  of  variation  in 
light  stimulation  but  in  the  habits  and  necessities  of 
existence  of  the  creature  in  its  usual  surroundings. 

Spaulding  found  that  hermit  crabs,  when  undisturbed, 
sought  the  lighter  portions  of  the  aquarium,  though  when 
threatened  by  an  enemy  they  sometimes  hid  in  dark 
corners.  He  found  that  if  food  was  placed  behind  a 
screen  where  it  was  dark  they  moved  toward  it  as  the 
chemical  stimulus  from  it  came  to  them.  Food  was  placed 
there  day  after  day,  immediately  after  inserting  the  screen 


TYPES   OF   ANIMAL   BEHAVIOR  63 

and  after  a  while  they  would  go  behind  the  screen  when  it 
was  put  in  place  though  there  was  no  food  there.  This 
seems  to  be  a  case  of  learning  by  experience  to  respond 
to  a  light  stimulation  in  a  way  slightly  opposed  to  the  in- 
stinctive mode  of  reacting  to  such  stimulations.  This 
habit  persisted  for  a  number  of  days.  To  other  forms  of 
stimulation  the  crab  does  not  readily  change  his  mode  of 
reaction.  Bethe  found  that  crabs  that  took  refuge  in 
a  dark  corner  continued  to  do  so,  although  they  were  mal- 
treated every  time  they  went  into  that  corner.  It  has  also 
been  found  by  Ransom  that  the  antennae  of  a  crab  may  be 
clipped  off  by  shears  again  and  again  without  his  learning 
to  react  to  the  suggestive  visual  stimulus  of  the  shears, 
although  he  draws  back  every  time  the  antennae  are  cut. 
Yerkes  found  that  crabs,  after  from  forty  to  two  hundred 
and  fifty  trials,  aUvays  took  the  right  path  to  the  aquarium. 
These  experiments  indicate  that  the  crab's  reactions  to 
visual  stimuli  may  be  modified,  after  a  number  of  trials, 
by  faA^orable  results,  but  that  unfavorable  results  do  not 
readily  change  reaction  so  as  to  inhibit  an  instinctive  tend- 
ency. 

Reactions  to  stimulations  other  than  those  of  light  are 
well  illustrated  by  Bell's  experiments  upon  the  reactions 
of  crawfish  to  chemical  stimuli.  He  found  that  chemical 
stimuli,  such  as  meat  juice,  acid,  salt,  etc.,  were  responded 
to  more  or  less  definitely  when  applied  to  any  portion  of  the 
body,  but  that  in  general  the  responses  were  more  vigor- 
ous and  definite  in  the  anterior  portions,  especially  those 
around  the  mouth.  The  reactions  to  meat  juice  were  in 
general  positive ;  that  is,  such  as  tended  to  give  the  animal 
more  of  the  stimulus,  the  movements  made  often  being 


64  GENETIC    PSYCHOLOGY 

such  as  would  bring  a  solid  particle  of  food  into  the  mouth 
if  the  chemical  stimulus  had  come  from  such  a  particle. 
The  reactions  to  lavender  water,  to  acids,  and  to  salt  were 
clearly  of  the  opposite  character,  often  being  so  definite 
that  the  exact  spot  affected  was  rubbed.  The  reactions 
to  the  other  fundamental  taste  stimuli,  sweet  and  bitter, 
were  very  slight. 

When  food  is  placed  in  the  water,  crawfish  do  not  go  to 
it  in  response  to  the  visual  stimulation,  but  after  a  little 
time  they  move  in  rather  an  uncertain  or  trial  manner 
toward  it,  evidently  being  directed  by  the  chemical  rather 
than  by  the  visual  stimulation.  When  they  come  in  con- 
tact with  food,  it  is  seized  by  a  very  definite  movement ;  but 
the  same  is  true  when  they  are  touched  by  stones  and  other 
inedible  food  particles.  When  out  of  the  water  they  will 
not  move  toward  meat  though  it  is  quite  near  them.  This 
may  be  because  they  are  not  sensitive  to  a  chemical 
stimulus  in  gaseous  form  or  it  may  be  because  of  their 
instinctive  tendency  to  feed  only  when  in  the  water. 

Crustacea  are  affected  to  a  slight  extent,  if  at  all,  by  sound 
stimulations.  The  otocysts  with  which  they  are  provided 
are  probably  stimulated  by  vibrations  of  the  water  and  by 
changes  in  position  in  maintaining  equilibrium,  but  reac- 
tions to  sounds  do  not  seem  to  play  any  part  in  their  usual 
behavior. 

FISHES 

In  fish  we  have  a  still  further  complication  of  reaction 
to  light.  It  is  no  longer  a  response  to  the  mere  chemical 
effects  of  light,  as  in  the  lower  forms  of  animal  life,  nor  to 
shadows,  as  in  mollusks,  nor  to  objects  varying  in  size  and 


TYPES   OF   ANIMAL   BEHAVIOR  65 

brightness  as  in  Crustacea,  but  a  response  varying  accord- 
ing to  the  color  of  objects.  This  has  been  proved  by  experi- 
ments of  Washburn  and  Bentley  upon  a  creek  chub.  The 
fish  was  fed  with  forceps  upon  which  were  red  and  green 
strips  of  wood,  but  he  was  allowed  to  have  the  food  only 
when  it  was  on  the  red  forceps.  The  instinctive  tendency 
to  snap  at  the  food  was  so  strong  that  the  failure  to  get  it 
from  the  green  forceps  did  not,  after  many  repetitions, 
inhibit  the  movement.  When,  however,  both  forceps  were 
disclosed  to  view  at  once,  the  red  with  food  and  the  green 
without,  the  fish  learned,  after  about  twenty-five  trials, 
to  go  to  the  red  forceps,  showing  that  he  was  differently 
affected  by  the  two  colors.  This  was  true  after  the  dark 
red  was  changed  to  light  red  and  after  the  green  was  re- 
placed by  blue.  The  fish  would  also  go  to  the  red  forceps 
when  both  were  empty  and  this  was  sometimes  true  even 
when  the  food  was  in  sight  near  him. 

The  attempt  was  made  to  reverse  this  reaction  to  color 
that  had  been  developed  by  training,  by  putting  the  food 
on  the  green  forceps  and  leaving  the  red  empty.  The  fish 
snapped  at  the  red  fourteen  times,  then  at  the  green,  but 
failed  to  get  the  food.  It  then  returned  and  snapped  at 
the  red  again  thirteen  times.  After  long  practice,  however, 
it  learned  to  go  to  the  green  first.  In  the  process  of  learn- 
ing, it  would  do  this  immediately  after  having  had  a  number 
of  trials,  with  considerable  certainty,  but  the  next  day  it 
would  be  more  likely  to  go  to  the  red  the  first  time.  Finally, 
however,  a  positive  reaction  to  green  was  established. 

The  fish  has  a  more  completely  developed  auditory 
apparatus  than  the  Crustacea,  and  experiments  have  shown 
that  it  is  affected  not  only  by  vibrations  produced  in  the 


66  GENETIC    PSYCHOLOGY 

water,  but  by  sounds  made  outside  of  the  water,  although 
its  behavior  does  not  seem  to  be  determined  to  any  con- 
siderable extent  by  auditory  stimuli.  The  lateral-line 
canals  extending  along  the  sides  of  the  fish  probably  in- 
crease the  sensitiveness  to  vibrations  of  the  water. 

AMPHIBIA 

In  animals  of  this  class,  of  which  frogs  and  turtles  are 
common  types,  a  much  greater  variety  of  behavior  is 
necessary  than  in  the  case  of  fishes  which  live  in  the  water 
all  of  the  time.  Some  of  the  amphibia  live  in  the  water 
most  of  the  time,  while  others  live  almost  entirely  on  land. 
Their  behavior  is  considerably  more  complex  than  that  of 
even  the  higher  Crustacea,  which  can  exist  for  a  considerable 
time  out  of  the  water  but  spend  most  of  their  lives  in  it. 

In  the  frog  sight  seems  to  be  the  dominant  sense,  par- 
ticularly when  stimulated  by  a  moving  object.  Although 
it  does  not  react  directly  to  all  moving  objects,  it  is  very 
sensitive  to  such  stimulation.  Experiments  of  Yerkes  show 
that  its  reactions  to  stimulations  of  the  skin  are  modified 
very  definitely  by  the  stimulus  of  a  moving  object.  If  the 
moving  object  is  seen  about  one  tenth  of  a  second  before  the 
stimulus  is  given,  the  reaction  is  reenforced,  while  if  it  is 
given  less  than  a  twentieth  of  a  second  before  the  stimulus 
the  reaction  is  inhibited.  This  reenforcing  and  inhibiting 
effect  of  stimulation  given  at  nearly  the  same  time  that 
reaction  to  another  stimulus  is  being  tested,  is  of  the  same 
nature  as  has  been  found  in  many  experiments,  notably 
those  upon  the  tendon  reflex  in  man. 

Frogs  rarely  react  directly  to  sound  stimuli,  although 


TYPES   OF   ANIMAL   BEHAVIOR  67 

they  have  a  pretty  well  developed  auditory  apparatus  and 
will  themselves  make  sounds.  The  chief  sound  to  which 
they  respond  at  almost  any  time  is  that  made  by  another 
frog  jumping  into  the  water.  At  the  breeding  season  the 
females  respond  very  definitely  to  the  call  of  the  male. 
Under  laboratory  conditions  it  appears  to  be  impossible 
to  get  any  direct  response  to  sound  stimuli  of  any  kind. 
It  is  found,  however,  that  sound  as  well  as  light  exerts  an 
inhibiting  or  enforcing  effect  when  given  at  the  time  or 
just  before  a  reflex  movement  is  being  made.  In  this  way 
Yerkes  showed  that  they  were  thus  affected  by  sounds 
varying  in  vibration  rate  from  fifty  to  ten  thousand. 

Tortoises  seem  to  be  higher  in  the  scale  of  intelligence 
than  frogs.  They  react  quite  definitely  to  objects  of  vari- 
ous kinds  and  to  sounds  of  certain  kinds.  To  what 
extent  they  discriminate  color  has  not  yet  been  determined. 
Yerkes  found  that  a  tortoise  could  learn  a  complicated  path 
in  five  trials  as  perfectly  as  crabs  could  learn  a  simpler  path 
in  forty.  Their  behavior  is  therefore  much  more  subject 
to  modification  than  that  of  the  Crustacea  and  also  than  that 
of  most  fishes.  One  of  the  marked  differences  between 
land  and  water  tortoises,  as  shown  by  Yerkes'  experiments, 
is  in  their  space  and  gravity  perceptions,  or,  in  other  words, 
their  reactions  when  there  is  no  stimulus  giving  them  the 
sense  of  support.  Water  tortoises  that  are  used  to  getting 
out  on  the  land  and  on  logs  or  rocks  and  jumping  off 
into  the  water  when  danger  threatens,  crawled  oft'  boards 
elevated  from  the  floor  without  hesitation,  while  land  tor- 
toises, like  most  other  land  animals,  reacted  in  a  negative 
way  whenever  stimuli  giving  a  sense  of  support  were  lack- 
ing.    Vision  seemed  to  play  a  large  part  in  such  sense  of 


68  GENETIC   PSYCHOLOGY 

support  and  the  hesitation  was  greater  with  increased 
height  of  the  board  from  the  floor.  When  blindfolded,  the 
land  tortoises  became  cautious  about  moving,  and  in  some 
instances  drew  back  soon  enough,  after  a  foot  had  passed 
beyond  the  board,  to  prevent  falling. 

INSECTS 

The  characteristics  of  insect  behavior  are  perhaps  best 
shown  in  Holmes'  experiments  upon  the  common  water 
scorpion  or  needle  bug,  ranatra  fiisca.  These  creatures 
are  capable  of  living  on  land,  though  they  spend  most  of 
their  time  in  the  water  and  they  are  able  to  walk,  swim,  or 
fly.  This  implies  considerable  complexity  of  organization, 
and  yet  careful  experiment  shows  that  they,  more  than 
almost  any  other  creature,  are  composed  of  parts  capable 
of  acting  reflexly,  to  a  considerable  extent  independently 
of  other  parts,  and  that  the  reactions  of  the  whole  animal 
are  determined  largely  by  the  results  of  these  separate 
reflexes. 

Few  if  any  creatures  react  with  such  definiteness  to 
light  and  contact  stimuli.  It  follows  accurately  with  its 
head  all  movements  of  a  light  when  in  a  dark  room.  If 
the  light  is  above  or  behind,  it  raises  its  head  up ;  if  it  is  in 
front  or  below,  its  head  is  bent  down.  If  the  light  is  moved 
from  side  to  side  in  front,  the  head  follows  it  with  more 
and  more  accuracy  as  the  act  is  repeated.  If  the  light  is 
brought  further  around  to  one  side  the  body  tips  toward 
that  side.  The  longer  it  is  stimulated  by  light  the  more 
perfectly  does  it  come  under  its  influence.  When  very 
much  excited  it  may  use  its  wings  in  following  the  light. 


TYPES    OF   ANIMAL    BKILW'IOR  69 

At  such  times  it  is  not  easily  afTected  by  any  other  stimulus 
and  cannot  readily  be  thrown  into  the  death  feint.  If  it  is 
placed  on  its  back  at  this  time,  it  will  move  toward  the 
light  without  taking  time  to  turn  over. 

The  creature  is  not,  however,  always  positively  photo- 
tactic.  If  it  has  been  in  the  dark  for  a  long  time,  it  reacts 
to  light  with  less  vigor  and  usually  in  a  negative  way. 
This  is  true  of  the  leg  movements,  which  are  exactly  the 
reverse  of  what  they  are  in  the  usual  condition,  although 
head  movements  are  not.  A  negativ-e  condition  may  also 
be  produced  by  picking  up  a  ranatra  by  its  breathing  tube 
and  dropping  it  into  the  water.  This  is  probably  because 
in  nature  a  mode  of  reaction  to  light,  the  opposite  to  the 
usual  one,  is  of  advantage  in  the  presence  of  danger.  The 
negative  condition  is  produced  more  readily  by  dipping  or 
dropping  into  the  water  than  by  handling  either  in  or  out 
of  the  water.  If  the  water  is  warm,  the  negative  state  is 
more  quickly  replaced  by  the  positive. 

Reactions  to  light,  under  experimental  conditions,  are 
not  always  favorable  to  self-preservation.  It  will  continue 
to  move  toward  a  light  when  in  the  positive  condition,  al- 
though the  heat  becomes  so  great  as  to  injure  and  destroy 
it.  This  is  not  because  the  movement  cannot  be  checked 
in  time  to  stop  the  injurious  stimulus  before  it  has  become 
fatal,  for  the  creature  moves  very  slowly  and  its  very  last 
feeble  effort  at  moving  is  toward  the  light  that  is  destroying 
its  life.  This  may  be  interpreted  as  a  purely  mechanical 
reaction  that  is  ordinarily  advantageous,  but  under  these 
unusual  circumstances  is  fatal.  It  has  also  been  inter- 
preted as  an  instance  of  voluntary  persistence  in  action 
that  is  subjectively  pleasurable  in  spite  of  the  fact  that  it  is 


70  GENETIC  PSYCHOLOGY 

objectively  destructive  to  the  organism.  As  we  shall  see 
later,  this  interpretation  may  be  true  of  man's  acts  but  it  is 
not  likely  that  it  ever  is  of  those  of  any  other  animal. 

In  general,  the  creature  does  not  react  to  more  than  one 
stimulus  at  a  time.  If  it  is  rubbing  its  wings  or  feeding 
or  is  in  close  contact  with  its  mate,  it  is  not  likely  to  react 
to  light,  unless  it  be  to  a  slight  extent  with  its  head. 

Symmetrical  balance  of  parts  is  probably  an  important 
factor  in  determining  the  movements  of  the  creature  as  a 
whole.  If  the  brain  is  divided  in  the  middle  there  is  some 
twitching,  indicating  sensitiveness  to  light  stimulation,  but 
none  of  the  characteristic  movements  of  the  body  either 
positive  or  negative  in  response  to  the  light.  When  the 
brain  is  intact  and  one  eye  blackened  over  or  destroyed,  the 
creature  moves  in  a  circle.  If  one  eye  is  partly  blackened 
over,  there  is  a  tendency  to  circular  movement  which  is 
usually  more  or  less  perfectly  corrected.  Experience 
seems  to  modify  the  reaction  in  this  respect,  for  after  a 
number  of  trials  an  individual  with  one  eye  blackened  was 
found  to  take  a  more  and  more  direct  course  toward  the 
light.  The  effect  of  experience  was  still  further  shown 
in  the  fact  that  after  the  animal  had  turned  in  one  direc- 
tion a  number  of  times  in  order  to  move  toward  a  light  in  a 
certain  position,  it  would  continue  to  turn  in  that  direc- 
tion, even  when  it  was  faced  in  such  a  way  that  it  would  be 
more  direct  and  more  natural  for  it  to  turn  in  the  other 
direction  and  move  toward  the  light.  The  results  of 
blackening  portions  of  the  compound  eye  seem  to  indicate 
that  different  parts  of  each  eye  are  connected  with  the 
movement  of  special  parts  of  the  body. 

Although  capable  of  learning  by  experience,  its  move- 


TYPES   OF   ANIMAL   BEHAVIOR  7I 

ments  seem  to  be  determined  largely  by  reflex  mechanisms, 
very  few  of  them  being  of  a  trial  character.  In  the  unusual 
condition,  however,  when,  with  one  eye  blackened  the 
animal's  mechanism  is  being  modified  so  that  the  creature 
can  move  more  directly  toward  the  light,  its  movements 
are  to  some  extent  of  an  mdefinite  and  trial  character. 

A  study  of  the  death  feint  shows  that  it  is  affected  by  heat, 
light,  and  by  the  number  of  times  the  feint  has  just  been 
produced.  If  the  head  is  removed,  the  body  reacts  in  the 
usual  form  of  death  feint,  though  the  feint  does  not  last  so 
long.  When  the  body  is  cut  in  two,  the  anterior  portion 
shows  the  death  feint,  and  other  reflexes  much  as  in  the 
normal  animal.  The  same  is  true  of  the  rear  portion  but 
in  a  less  degree.  Ganglia  located  in  the  different  parts 
doubtless  make  this  possible. 

What  has  been  found  of  the  reaction  of  the  ranatra 
seems  to  be  in  general  true  to  a  greater  or  less  extent  of 
all  insects.  Most  of  their  reactions  are  of  a  definite  reflex 
character,  each  part  of  the  creature  reacting  separately 
in  its  characteristic  way,  and  yet  the  animal  as  a  whole 
may  have  its  actions  modified  to  some  extent  by  experience. 

The  perfectness  with  which  the  inherited  structure  of 
insects  fits  them  for  the  life  they  are  to  lead,  in  cases  where 
there  is  no  possibility  of  learning  by  experience,  is  illus- 
trated by  the  changed  activities  of  insects,  such  as  the 
blister  beetle,  in  the  different  forms  that  it  assumes  in 
different  stages  of  its  development.  This  creature,  in 
its  first  stage,  moves  actively  on  six  legs  and  finds  a  home 
on  a  bee,  where  it  remains  till  the  bee  lays  its  eggs,  when  it 
feeds  on  them.  It  then  changes  into  a  grub,  with  minute 
feet   and  rudimentary  masticating  organs,  and  feeds  on 


72  GENETIC    PSYCHOLOGY 

honey.  It  winters  in  a  pupa-like  state  and  emerges  as  an 
adult  beetle  with  mouth,  legs,  and  wings,  ready  to  feed 
upon  leaves  and  to  lay  its  eggs  under  the  nest  of  a  burrow- 
ing bee,  which  is  to  be  the  host  of  its  young.  With  no 
chance  whatever  for  learning  what  to  do  it  does  just  the 
one,  of  an  infinite  number  of  things,  in  each  stage,  that  will 
preserve  the  species. 

This  beetle  also  illustrates  another  prominent  charac- 
teristic of  insects.  Their  behavior,  more  than  that  of  any 
other  species  of  animals,  is  governed  by  the  necessity  of 
preserving  the  life  of  the  species  rather  than  of  carrying 
on  their  own  individual  life.  A  large  proportion  of  this 
beetle's  activities  are  concerned,  not  with  securing  food 
and  protection  for  itself,  but  with  securing  food  and  protec- 
tion for  the  next  generation. 

Much  time  has  been  spent  in  studying  the  behavior  of 
insects,  especially  ants,  bees,  and  wasps.  Nowhere  has 
there  been  greater  difference  of  opinion  in  interpreting 
the  behavior  of  animals  than  in  the  case  of  these  creatures. 
Some  look  upon  them  as  nothing  more  than  a  combination 
of  reflex  mechanisms  which  result  in  their  performing  the 
usual  acts  of  their  species  with  little  or  no  modification  by 
experience  or  individual  variation ,  while  others  ascribe  to 
them  intellectual  and  moral  qualities  rivaling  in  number 
and  degree  those  of  man.  A  careful  study  of  their  be- 
havior leaves  no  doubt  that  most  of  their  actions  are  largely 
of  a  reflex  or  instinctive  character.  Yet  there  are  consider- 
able variations  from  the  typical  mode  of  reaction  in  individ- 
ual insects  and  some  ability  to  learn  by  experience.  The 
ability  to  find  the  way  to  their  nests  and  to  food  is,  by  native 
endowment,  considerable  in  most  insects,  and  in  order  to 


TYPES    OF    ANIMAL    BKIIAVIOR  73 

be  of  p^ractical  use  there  must  be  some  possibility  of  modifi- 
cation of  reaction  to  surroundings  in  order  that  an  individ- 
ual may  be  able  to  return  to  places  thai  it  has  previously 
visited.  Experiments  show  that  changes  in  the  surround- 
ings of  a  nest  may  cause  a  wasj)  to  fail  to  recognize  her  nest 
when  she  comes  to  it.  Changes  in  large  colored  cards 
that  had  been  near  the  nest  for  some  time  were  found 
by  the  Peckhams  to  cause  confusion  and  failure. 

]\Iany  of  the  acts  of  ants  that  seem  to  be  directed  by 
intelligence  similar  to  that  of  man  are  doubtless  to  be 
explained  as  slight  variations  in  habitual  reactions.  For 
example,  some  ants  that  were  cut  off  from  food  supply 
by  birdlime  or  tobacco-soaked  cloth,  built  a  bridge  of 
pellets  of  earth  and  thus  were  able  to  reach  the  food.  In 
another  case  a  watch  glass  was  filled  with  water  and  some 
pupae  were  placed  on  the  small  island  in  the  center  of  it. 
After  apparently  trying  to  reach  the  pupa?,  one  ant  began 
throwing  debris,  others  joined,  and  soon  there  was  a  bridge 
on  which  they  crossed  and  carried  away  the  pupie.  These 
acts,  which  at  first  thought  seem  to  indicate  conscious 
foresight  and  intelligence,  may  take  on  quite  a  different 
form  when  considered  in  relation  to  their  usual  behavior. 
It  is  the  custom  of  ants  to  cover  sticky  or  wet  objects  near 
their  nests  with  debris  and  this  is  probably  the  explanation 
of  both  cases  of  apparently  intentional  bridge-building. 
In  the  course  of  this  process  the  animals  got  near  the  food 
particles  in  one  case,  and  in  the  other  near  the  pupic,  and 
according  to  their  usual  mode  of  behavior  immediately 
seized  them.  The  fact  that  ants  cover  objectionable 
places  with  debris  excites  little  comment.  Neither  is  much 
notice  taken  of  the  fact  that  they  carry  food  or  pupte  away 


74  GENETIC  PSYCHOLOGY 

when  they  find  them.  The  chance  occurrence  of  these 
two  modes  of  behavior  in  immediate  succession  is  what 
excites  wonder  and  leads  some  to  the  probably  erroneous 
interpretation  of  the  ants'  behavior  as  an  instance  of  fore- 
thought and  planning  of  means  to  ends. 

Many  other  seemingly  remarkable  actions  of  ants  are 
subject  to  correspondingly  simple  interpretations.  It  has 
been  claimed  that  they  imitate  each  other,  but  it  is  found 
that  ants  which  have  no  chance  to  learn  by  imitation  per- 
form the  usual  actions  of  their  species  with  the  same  skill 
and  exactness.  The  so-called  slave  ants  perform  the 
same  acts  in  their  new  home  that  were  characteristic  of 
them  in  the  home  nest.  In  the  wars  of  ants,  behavior 
supposed  to  correspond  with  the  act  of  making  peace  be- 
tween armies  has  been  observed.  This  phenomenon, 
like  that  of  the  seemingly  remarkable  memory  of  ants  for 
their  companions,  may  readily  be  explained  on  the  basis 
of  their  usual  behavior.  Ants  from  a  foreign  nest  are 
treated  as  enemies  because  of  their  odor,  while  those  of  the 
same  nest  have  the  odor  associated  with  friendly  behavior. 
In  a  battle,  where  the  opponents  mingle,  they  become  used 
to  the  scent  of  the  enemy,  which  is  mixed  to  a  greater  or 
less  extent  with  that  of  friends,  and  this  decrease  in  the 
usual  sensory  stimulus  to  fighting  would  naturally  result 
in  the  so-called  actions  of  making  peace. 

The  behavior  of  ants  of  the  same  species  is  practically 
the  same  in  whatever  portion  of  the  world  they  are  found. 
All  are  capable,  however,  of  varying  slightly  their  mode  of 
reaction  to  suit  some  of  the  common  variations  in  environ- 
ment, and  there  are  also  individual  differences  in  vigor  and 
persistency  of  action  and  in  sensitiveness  to  different 
varieties   of   stimuli. 


TYPES   OF  ANIMAL   BEHAVIOR  75 

In  no  case  are  the  changes  in  behavior  of  individual  ants 
such  as  involve  any  marked  variation  from  instinctive 
modes  of  reaction,  although  they  may  result  in  two  ants 
acting  quite  differently  under  the  same  circumstances. 
For  example,  two  ants  observed  by  Turner  acted  in  quite 
different  ways  as  a  result  of  their  experience  in  carrying 
pupae  from  an  elevated  stage.  One  had  learned  the  route 
down  an  inclined  plane,  the  other  had  not  been  able  to 
learn  this  route  but  had  tumbled  off  the  edge  with  the  pupae. 
After  being  lifted  to  the  stage  several  times  with  a  pair  of 
pincers,  it  learned  to  go  to  a  certain  place  to  get  on  the 
pincers  to  be  lifted,  while  the  ant  that  had  learned  to  find 
its  way  up  and  down  the  inclined  plane,  dodged  the  pincers 
whenever  they  were  brought  near  him. 

Turner's  experiments  indicate  that  ants  are  not  directed 
by  odor  in  finding  their  way  to  such  an  extent  as  has  been 
supposed.  He  finds  them  sensitive  to  the  visual  stimula- 
tion of  objects,  to  differences  in  tactile  stimulation  from  a 
rough  or  smooth  surface,  to  differences  in  direction  of 
surface,  as  inclining  up  or  down,  to  differences  in  direction 
of  light,  and  to  differences  in  sounds.  All  of  these  stimu- 
lations, except  the  latter,  help  to  guide  the  animal  in  finding 
his  way  to  his  nest.  Variations  in  any  of  them  may  cause 
hesitation  or  mistakes^  and  the  same  is  true  of  variations 
in  odor ;  but  the  ant  seems  to  react  to  the  general  direction 
and  the  general  situation  rather  than  to  depend  upon  just 
one  form  of  sensory  stimulus.  In  going  to  his  nest,  he  does 
not  always  take  exactly  the  same  course  and  after  taking 
several  courses  he  often  learns  to  take  habitually  the  short- 
est one.  This  indicates  that  he  is  affected  by  differences 
in  distance. 


76  GENETIC    PSYCHOLOGY 

Turner  docs  not  find  cooperation  in  tasks  as  prominent 
in  ants  as  has  been  supposed.  He  observes  no  instance 
of  their  showing  evidence  of  communication  by  means 
of  their  antennae.  They  do  not  thus  induce  another  ant 
to  follow,  but  if  an  ant  is  lost,  it  may  be  carried  to  the  nest 
by  its  companions  wlio  find  it.  Ants  often  carry  food  or 
pupae  some  distance ;  then,  because  they  get  lost  or  for  some 
other  reason,  drop  their  load.  Any  other  ant  finding  it 
carries  it  to  the  nest.  By  coincidence  this  sometimes 
results  in  ants  seeming  to  cooperate  by  carrying  food  part 
way  to  the  nest  and  leaving  it,  while  others  carry  it  the 
rest  of  the  way.  An  interesting  instance  of  this  kind  is 
reported  by  Gredlcr.  Some  ants  had  learned  a  round- 
about route  to  a  bottle  of  sugar  which  they  were  carrying 
grain  by  grain  to  their  nest.  Later  it  was  observed  that 
some  of  the  ants  were  carrying  the  sugar  out  of  the  bottle, 
which  was  suspended  by  a  string,  and  dropping  it  to  the 
window  sill,  while  others  were  carrying  it  to  the  nest.  This 
is  undoubtedly  an  instance  of  cooperation,  but  one  due  in 
all  probability  to  chance  rather  than  to  intention. 

MAMMALS  —  GUINEA    PIGS 

In  the  case  of  all  animals  previously  noticed  there  is 
little  difference  between  the  structure  and  behavior  of  the 
young  and  the  adults  of  the  same  species,  except,  of  course, 
in  the  case  of  animals  that  have  different  forms  at  different 
stages  of  development,  such  as  insects  and  frogs.  In  the 
guinea  pig  we  have  an  example  of  a  mammal  that  is  at 
birth  practically  the  same,  in  both  external  and  internal 
structure  and  in  behavior,  that  it  is  at  maturity,  except 


TYPES   OF   ANIMAL   BEHAVIOR  77 

that  at  birth  it  is  smaller  and  not  sufficiently  strong  to 
make  many  or  vigorous  movements. 

Observation  and  experiments  by  Allen  show  that  any- 
thing which  the  guinea  pig  is  capable  of  learning  can  be 
learned  when  two  or  three  days  old  as  readily  as  at  any 
other  age.  It  is  capable  of  learning  only  a  few  things, 
but  whatever  it  can  learn  is  acquired  without  very  many 
trials  and  the  effects  of  such  modification  in  behavior 
persist  after  many  weeks.  In  finding  its  way  tlirough  a 
simple  maze  to  food  or  companions,  the  superfluous  move- 
ments, such  as  biting  at  a  wire  and  going  into  blind  alleys 
and  other  extra  movements  of  play  and  curiosity,  are  not 
numerous  (as  they  often  are  in  higher  animals),  and,  if 
success  is  attained  at  all,  do  not  continue  long.  A  habit 
once  formed  is  not  readily  changed,  and  a  path  that  has 
led  to  success  continues  to  be  followed  though  there  may 
be  much  shorter  ones. 

The  guinea  pig  is  provided  with  all  the  sense  organs 
of  higher  animals  but  seems  to  be  guided  in  its  movements 
chiefly  by  vision  and  by  the  sensations  of  movement,  though 
it  is  quite  responsive  to  sounds  made  by  its  companions. 
In  vision  it  is  especially  sensitive  to  moving  objects,  but  it 
probably  has  little  if  any  clear  perception  of  form  and 
color,  since  its  eyes  arc  so  situated  that  they  cannot  act 
together,  and  since  there  is  little  difference  between  the 
central  and  peripheral  portions  of  the  retina.  Although 
probably  night  animals  in  their  natural  habitat,  they  find 
their  way  more  quickly  and  with  fewer  random  movements 
in  the  light  than  in  the  dark.  Colored  lights  or  objects 
do  not  seem  to  be  of  any  significance  in  directing  their 
movements  along  a  certain  path  or  into  a  compartment. 


78  GENETIC    PSYCHOLOGY 

Neither  does  contact  with  the  sides  serve  as  a  guide. 
Differences  in  the  appearance  of  food  boxes  or  of  food 
seem  to  have  no  influence  upon  their  actions.  They  simply 
react  to  their  general  surroundings  by  movements  along 
a  certain  course. 

Guinea  pigs  care  for  their  young  to  some  extent,  but 
for  a  short  time  only.  They  react  in  characteristic  ways 
to  the  actions  of  their  mates,  especially  to  danger  signals. 
They  also  have  sexual  calls,  and  frequently  make  a  chuc- 
kling sound,  which,  when  started  by  one,  is  taken  up  by 
others.  In  these  responses  to  social  stimuli,  the  guinea 
pig  shows  a  considerable  advance  over  the  lower  verte- 
brates; but  in  this  and  other  reactions  there  is  no  great 
superiority  to  insects. 

WHITE   RATS 

The  white  rat  at  maturity  is  a  much  more  active  animal 
than  the  guinea  pig  and  capable  of  doing  a  great  many 
things  with  teeth  and  claws  that  are  physically  impossible 
to  the  guinea  pig  and  which  are  entirely  too  complex  for 
him  to  learn.  While  a  white  rat  may  learn  to  pull  a 
string  or  turn  a  button  and  push  against  a  door  in  order 
to  get  food,  the  guinea  pig  does  not  of  himself  even  learn 
to  push  open  a  swinging  door  at  which  he  is  gnawing, 
though  by  so  doing  he  could  readily  obtain  food  and  com- 
panionship. In  the  mere  matter  of  learning  a  maze  there 
is  less  difference,  although  the  rat  is  very  much  superior 
in  the  quickness  with  which  he  moves  and  the  complexity 
of  maze  problems  which  he  can  solve.  The  sense  organs 
of  the  white  rat  are  very  similar  in  development  and  in 
relative  prominence  to  those  of  the  guinea  pig,  except  that 


TYPES    OF   ANIMAL   BEHAVIOR  79 

his  vision  is  considerably  better.  In  finding  his  way 
through  a  maze,  however,  vision  is  of  only  incidental 
assistance.  The  rat  is  probably  more  completely  a  night 
animal  than  the  guinea  pig,  and  he  finds  his  way  in  the 
dark  and  when  blinded  with  almost,  if  not  quite,  as  great 
rapidity  and  accuracy  as  when  he  has  full  use  of  his  eyes 
in  the  light.  Watson's  experiments  show  that  when  all 
the  senses  except  those  connected  with  movement  are 
eliminated,  by  means  of  operations  upon  the  sense  organs 
and  nerves  and  by  etherizing  the  feet  to  destroy  tactile 
sensations,  rats  learn  their  way  though  a  maze  with  little 
difficulty. 

Rats  are  much  more  active  than  guinea  pigs,  moving 
about  quickly,  clawing  and  biting  at  various  objects. 
For  this  reason  they  are  likely  to  find  their  way  out  of  a 
cage  or  into  a  box  where  food  is  to  be  obtained  even  when, 
to  do  so,  very  definite  acts  of  pulling  at  a  string  or  gnawing 
at  a  fastening  or  digging  and  pushing  at  a  certain  place, 
are  required.  After  the  act  has  once  been  performed, 
random  movements  rapidly  decrease,  the  animal  usually 
going  directly  toward  that  part  of  the  apparatus  where 
he  was  when  he  made  the  movement  that  released  him. 
After  a  few  trials  he  attacks  the  particular  part  of  the 
mechanism  necessary  and  soon  learns  to  make  just  the 
right  movements  to  effect  his  release.  Having  once 
learned  the  way  to  get  out  or  in  he  is  able  to  perform 
the  act  perfectly  after  long  intervals  without  practice; 
yet  if  changes  are  made  in  the  position  of  the  fastening 
or  the  mode  of  manipulating  it,  it  does  not  take  him  long  to 
modify  his  movements.  The  period  during  which  there 
occurs  continual  shortening  of  the  path  or  elimination  of 


8o  GENETIC   PSYCHOLOGY 

useless  movements  is  longer  than  in  the  case  of  the  guinea 
pig,  in  about  the  same  proportion  as  the  number  of  move- 
ments and  complexity  of  the  acts  which  he  can  learn  to 
perform,  is  greater. 

When  two  rats  are  together,  trying  to  solve  a  problem, 
each  is  affected  somewhat  by  the  actions  of  the  other. 
If  one  pauses  and  scratches  or  gnaws  at  a  certain  place, 
the  attention  of  the  other  is  likely  to  be  attracted  to  that 
place,  just  as  it  is  to  food,  when  another  rat  finds  and  begins 
eating  it.  The  movements  of  a  companion  serve  therefore 
to  suggest  and  call  forth  similar  movements  providing  they 
are  such  as  the  rat  has  some  instinctive  tendency  to  make 
in  the  same  situation  when  by  himself.  If  one  of  the  rats 
succeeds  in  getting  out,  the  other  follows  him.  After  this  has 
occurred  several  times,  the  one  that  does  not  know  how  to 
get  out  ceases  to  try  to  find  its  way  out  but  follows  the  other 
rat  around  and  as  soon  as  the  door  is  released,  passes  out. 

If  one  rat  is  placed  in  a  separate  compartment  where 
he  can  see  another  rat  get  out  again  and  again,  his  own 
actions  when  placed  in  that  compartment  are  no  different 
from  those  of  a  rat  that  has  seen  no  other  rat  escape 
from  it. 

When  in  the  same  compartment  with  a  trained  rat  he 
may  follow  the  other  rat  and  gnaw  and  scratch  at  parts  of 
the  cage  attacked  by  his  trained  companion,  yet  there  is 
no  evidence  that  he  perceives  the  exact  character  of  the 
movements  made  by  the  other  rat  and  thus  learns  to  per- 
form the  act.  If  he  learns  to  perform  it  at  all  it  is  through 
having  made  the  necessary  movement  in  a  chance  or  trial 
way.  The  movements  of  the  other  animal  appear  to  do 
nothing   more,   even   under  the   most   favorable  circum- 


TYPES    OF   ANIMAL    BEHAVIOR  8l 

stances,  than  direct  his  attention  to  the  portion  of  the  ap- 
paratus to  be  attacked.  In  Berry's  experiments  a  knot 
on  a  string  must  be  pulled  by  the  claws  in  order  to  release 
the  door,  the  string  being  too  high  to  be  reached  with  the 
teeth.  No  rat  was  able  to  learn  this  trick  without  teach- 
ing, and  no  rat  was  able  to  learn  the  trick  from  one  that 
had  been  trained  to  perform  it.  It  appears  therefore  that 
either  their  vision  is  not  perfect  enough  to  enable  them 
to  perceive  the  character  of  the  movement  made  by  a 
companion  or  they  do  not  and  perhaps  cannot  single  out 
from  the  whole  situation  such  a  movement  made  by  another 
and  then  execute  it  themselves.  So  far  as  the  results  of 
experiments  that  have  been  tried  thus  far  are  concerned 
it  seems  that  a  rat  can  learn  how  to  make  a  given  move- 
ment only  by  the  experience  of  making  it  himself  and  not 
by  observing  another  make  it. 

One  of  the  most  striking  differences  between  the  guinea 
pig  and  the  rat  is  the  difference  between  the  behavior  of 
the  young  and  of  the  adult.  While  the  guinea  pig  when 
two  or  three  days  old  can  learn  and  remember  whatever  it  is 
capable  of  learning,  as  perfectly  as  the  adult,  the  rat  at 
that  age  is  blind  and  helpless.  Not  until  the  rat  is  be- 
tween three  and  four  weeks  old  is  he  as  mature  in  his 
behavior  and  ability  to  learn  as  the  guinea  pig  is  when  the 
same  number  of  days  old.  The  complexity  of  acts  that 
he  can  i)crform,  however,  is  then  many  times  greater  than 
is  possible  for  the  guinea  pig. 

DOMESTIC    ANIMALS    AND    BIRDS 

Dogs,  cats,  pigeons,  chickens,  and  other  well-known 
animals  have  recently  been  made  the  subjects  of  careful 


82  GENETIC   PSYCHOLOGY 

experiments.  While  differing  greatly  in  the  relative 
prominence  of  the  different  senses  and  in  their  motor 
facility,  as  well  as  in  their  instinctive  behavior,  they  yet 
show  certain  common  characteristics,  especially  in  ex- 
periments of  the  maze  type.  They  all  depend  upon  sight 
more  than  does  the  guinea  pig  or  the  rat,  responding  not 
only  to  objects  of  different  size  but  to  specific  differences 
in  form  and  color.  They  all  learn  by  the  same  general 
method,  that  of  trial  and  success,  and  they  gradually  learn 
to  eliminate  useless  movements  after  they  have  once 
achieved  success.  Some  are  more  affected  than  others 
by  the  actions  of  their  companions,  but  in  no  case,  under 
experimental  conditions,  has  there  been  an  unquestioned 
instance  of  learning  how  to  do  a  thing  by  observing  any 
other  person  or  animal  do  it. 

One  exception  to  this  statement  regarding  imitation 
must  be  made.  Parrots,  crows,  and  a  number  of  singing 
birds  are  known  to  learn  new  sounds  from  hearing  them. 
If  separated  from  their  own  species  they  make  the  usual 
cries  and  danger  calls  but  do  not  generally  sing  the  songs 
characteristic  of  the  species.  They  learn  whatever  songs 
they  hear  that  they  are  capable  of  singing.  In  the  case  of 
parrots  and  crows,  as  is  well  known,  words  and  sentences 
are  sometimes  learned.  It  appears  therefore  that  the  vocal 
apparatus  is  to  some  extent  indeterminate  and  plastic  as 
it  is  in  man,  so  that  the  stimulus  of  sounds  heard  cause  it 
to  function  in  ways  that  reproduce  those  sounds.  It  may 
not  be  asserted  that  none  of  the  animals  so  far  mentioned 
ever  learn  a  new  movement,  other  than  those  made  by 
the  vocal  apparatus,  by  imitation ;  but  the  fact  remains, 
that,  as  yet,  under  experimental  conditions,  no  observer 


TYPES    OF   ANIMAL   BEHAVIOR  83 

has  found  a  single  unquestioned  example  of  such  learning 
by  imitation. 

As  in  the  case  of  the  rat,  movements  that  they  have  an 
instinctive  tendency  to  perform  are  sometimes  suggested 
by  perceiving  one  of  their  companions  perform  the  move- 
ment, and  their  attention  to  certain  objects  that  may  help 
them  in  getting  out,  may  be  attracted  by  the  movements 
of  companions  or  of  persons.  They  learn  less  rapidly 
w^hen  success  comes  after  an  accidental  movement  on 
their  part  than  when  it  comes  in  connection  with  an  effort 
to  get  out.  Thorndike  thought  that  they  could  not  be 
taught  by  being  put  through  the  movements,  but  other 
experimenters  have  succeeded  in  teaching  movements  in 
this  way  more  quickly  than  when  such  help  was  not  given. 

In  degree  of  helplessness  at  birth  and  in  the  length  of 
time  elapsing  before  maturity  there  are  great  differences 
among  the  birds  and  higher  mammals,  but  probably  none 
are  more  completely  mature  at  birth  than  the  guinea  pig, 
while  some  are  more  helpless  and  have  a  longer  period  of 
immaturity  than  the  rat.  All  show  considerable  individual 
variations  and  are  capable  of  great  individual  modification 
by  experience. 

RACCOONS    AND   MONKEYS 

These  animals  are  probably  superior  to  most  other 
animals  in  definiteness  of  vision,  and  they  have  a  motor 
apparatus  better  adapted  to  manipulating  objects  in  a 
variety  of  ways  than  any  others.  The  monkey  is  superior 
to  the  raccoon  in  this  respect,  but  the  raccoon  is  less  easily 
diverted  from  what  he  is  doing,  and  hence  frequently  solves 
his  problem  with  more  rapidity  and  sureness  than  the 


84  GENETIC    PSYCHOLOGY 

monkey.  Both  animals  show  great  facility  in  manipulat- 
ing apparatus  in  order  to  obtain  food  or  freedom.  The 
mere  act  of  manipulating  some  object  is,  for  both,  often 
a  sufficient  incentive  to  induce  them  to  learn  rather  com- 
plicated tricks,  when  there  is  no  food  or  other  reward  to 
be  obtained.  They  can  learn  not  only  to  open  a  door 
fastened  in  various  ways,  but  to  open  a  door  which  is  held 
in  place  by  three  or  four  devices  which  have  previously 
been  learned  alone. 

The  fact  that  the  fastenings  must  be  loosed  in  a  certain 
order  did  not,  in  Davis'  experiments,  increase  the  difficulty 
for  the  raccoon.  The  records  of  learning  such  combina- 
tions, and  of  their  memory  after  an  interval,  show  that  the 
order  is  more  readily  learned  and  less  likely  to  be  forgotten 
than  the  direction  and  force  of  movement  required  to  undo 
each  fastening.  In  Cole's  experiments  the  raccoons  varied 
the  order  in  which  they  attacked  the  several  fastenings. 

The  monkey  is  affected  more  by  the  actions  of  his  com- 
panions than  the  raccoon.  This  serves  sometimes  to 
divert  him  from  the  problem  upon  which  he  is  working, 
while  it  may  also  sometimes  help  him  in  learning  what  a 
companion  already  knows  how  to  do  by  directing  his 
attention  to  the  proper  place  and  object.  In  no  instance 
has  the  raccoon  been  known  to  learn  a  new  movement  from 
seeing  a  person  or  one  of  its  mates  perform  it.  Cole 
thought  his  own  movements  in  raising  cards  may  have 
helped  raccoons  to  learn  them,  but  impatience  to  have 
the  card  meaning  food  appear  may  have  led  to  scratch- 
ing at  the  place  from  which  it  had  previously  appeared. 
He  could  teach  raccoons  by  putting  them  through  the  act, 
but    they   learned    much    less    quickly  than   when    they 


TYPES   OF   ANIMAL    BEHAVIOR  85 

themselves  had  some  part  in  the  performance  of  the  act. 
They  learned  to  go  in  the  top  of  a  box  Ijy  being  lifted  in 
by  the  neck,  although  their  legs  hung  limp,  which  shows 
there  was  no  innervation  on  their  part. 

Monkeys,  contrary  to  the  usual  opinion,  arc  not  found 
by  experimenters  to  imitate  any  definite  movement  made 
by  persons,  although  the  actions  of  a  j)erson  may  serve 
as  an  effective  stimulus  to  monkeys  to  make  them  examine 
and  manipulate  objects.  Kinnamen,  in  his  studies  of 
the  monkey,  observed  two  instances  of  what  seemed  to 
him  clear  and  definite  imitations  of  the  movement  of  a 
companion.  One  instance  was  that  of  pulling  out  a  plug, 
the  other  that  of  pressing  down  a  lever.  In  both  cases 
the  monkey,  after  repeated  attempts,  had  failed  to  make 
the  right  movement,  although  he  had  worked  at  the  ob- 
jects with  considerable  persistence.  The  monkey  who 
knew  the  trick  pulled  out  the  plug  and  the  other  monkey 
immediately  afterwards  did  so  without  any  hesitation  or 
trial  movement.  The  same  was  true  in  the  case  of  the 
pressing  down  of  the  lever.  Since  only  two  cases  of  un- 
questioned imitation  in  the  most  highly  developed  and 
most  imitative  of  all  animals  have  as  yet  been  found  under 
experimental  conditions,  it  seems  absolutely  certain  that 
the  tendency  to  imitate  the  actions  of  persons  and  of  mates 
cannot  be  very  strong  in  any  animal  except  man,  in  whose 
behavior  and  learning  we  know  it  plays  a  very  prominent 
part. 

SUMMARY    OF    CHARACTERISTICS    OF    BEHAVIOR 

We  find  that  all  organisms,  from  the  lowest  to  the  highest, 
are  engaged  in  the  business  of  preserving  themselves  as 


86  GENETIC    PSYCHOLOGY 

individuals  and  as  species.  They  do  this,  not  as  passively 
moved  by  outside  forces,  but  in  response  to  stimuli  that 
set  free  energy  stored  up  within  them  which  is  expended  for 
the  good  of  the  creature  as  determined  by  its  structure. 

All  are  self-feeding,  self-repairing,  and  self-reproducing. 

The  behavior  of  all  is  affected  by  objects  that  touch 
them,  by  gravity,  light,  heat,  electricity,  and  chemicals. 

All  have  characteristic  modes  of  responding  to  these 
stimuli  of  different  intensities  but  none  respond  in  exactly 
the  same  way  to  the  same  stimuli  every  time.  Their 
responses  to  any  stimulus  vary  with  their  internal  states, 
especially  that  of  hunger,  and  with  variations  in  the  external 
conditions  accompanying  the  stimulus,  and  because  of  per- 
sisting effects  of  previous  stimuli  and  previous  movements. 

The  activity  of  all  organisms  is  usually  greater  when 
unfavorably  stimulated  or  when  hungry,  than  when  in  a 
more  favorable  condition  as  to  internal  states  and  in  rela- 
tion to  the  environment. 

Some  of  the  activity  of  all  animals  is  of  a  trial  character 
and  all  react  in  at  least  two  ways,  positively  to  favorable 
stimuli,  and  negatively  to  unfavorable  stimuli. 

Most  animals  have  modes  of  reaction  that  are  not  en- 
tirely of  a  trial  character,  but  are  likely  to  secure  at  once 
either  favorable  stimuli  or  freedom  from  unfavorable. 

Continuous  or  repeated  stimulation  leads  in  all  creatures 
sooner  or  later  either  to  temporary  or  permanent  modifica- 
tion in  behavior. 

We  see,  therefore,  that  there  is  no  essential  difference 
except  in  degree  and  complexity  in  the  fundamental  charac- 
teristics of  behavior  in  all  animals  from  the  lowest  of  the 
protozoa   to   the   highest    vertebrate,    man.     The   higher 


TYPES    OF   ANIMAL   BEHAVIOR  87 

animals  simply  specialize  and  add  to  the  characteristics 
of  the  lower. 

DIFFERENTIATION    OF    PHYSIOLOGICAL    PROCESSES 
AND    BEHAVIOR 

As  we  have  already  seen,  the  essential  nature  of  an  organ- 
ism implies  that  activities  are  constantly  taking  place 
within  it  by  means  of  which  its  existence  is  preserved.  In 
the  case  of  very  small  animals  in  a  liquid  medium  this 
internal  activity  is  directly  affected  by  the  environment. 
In  larger  animals  the  environment  cannot  directly  affect 
any  but  the  outer  portion  of  the  body  and  that  is  often 
protected  to  a  considerable  extent.  The  processes  taking 
place  within  the  body  are  therefore  only  indirectly  related 
to  the  environment.  In  the  smaller  animal  it  is  difhcult 
to  draw  any  sharp  line  of  distinction  between  vegetative, 
somatic,  or  physiological  processes,  and  the  reactions  by 
which  the  creature  comes  into  relation  with  his  environ- 
ment. In  other  words,  behavior  is  not  clearly  differenti- 
ated from  physiological  processes.  In  the  larger  and  higher 
animals  the  bodily  processes  taking  place  within  the  animal 
are  usually  very  easily  distinguished  from  behavior  or 
movements  in  response  to  environmental  stimuli.  In 
even  the  highest  animals  the  physiological  processes  are, 
however,  readily  affected  by  external  stimulation  and 
by  movements;  while,  on  the  other  hand,  the  behavior 
varies  with  the  physiological  condition.  The  relation, 
however,  is  an  indirect  one,  while  in  the  simpler  organisms 
the  relation  between  light,  air,  heat,  etc.,  and  the  physio- 
logical processes,  is  so  direct  that  physiological  activity 
can  scarcely  be  distinguished  from  behavior. 


88  GENETIC   PSYCHOLOGY 

As  we  go  upward  in  the  scale  of  animal  life  we  find  not 
only  that  physiological  processes  and  behavior  are  differen- 
tiated, but  that  there  are  many  other  specializations  and 
complications.  The  process  of  nutrition  becomes  special- 
ized into  processes  of  respiration,  digestion,  and  circula- 
tion, and  each  of  these  is,  in  the  higher  animals,  still 
further  specialized  so  that  one  part  of  the  process  takes 
place  in  one  organ  and  another  part  in  another. 

Behavior  is  also  specialized  into  (i)  that  which  has  be- 
come a  fixed  characteristic  of  the  species,  and  (2)  more 
temporary  modes  of  activity  produced  by  the  experience 
of  the  individual. 

In  the  lower  animals  there  is  little  difference  between  the 
behavior  of  the  species  and  of  the  individual,  but  in  the 
higher  animals  the  individual  acquires  many  new  modes 
of  behavior.  These  are  sometimes  simply  modifications 
of  the  instinctive  behavior  of  the  species  and  involve  noth- 
ing more  than  specialization  in  instinctive  modes  of  reac- 
tion. In  other  cases  modes  of  reaction  quite  different 
from  those  characteristic  of  the  species  are  acquired.  In 
such  cases  we  may  distinguish  a  further  basis  of  behavior 
in  the  form  of  capacities,  which  are  more  passive  and  more 
individual  in  their  character  than  the  instinctive  tenden- 
cies, and  therefore  subject  to  greater  modification  by  the 
activities  of  the  individual. 

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Spaulding,  E.  G.     An  Establishment  of  Association  in  Hermit  Crabs, 

Jr.  Comp.  Neu.  &=  Psych.,  Vol.  XIV,  pp.  49-61. 
*Thorndike,  E.  L.,  1899.      The  Instinctive   Reactions   of  Young 

Chicks,  Psych.  Rev.,  Vol.  VI,  p.  282. 
A  Reply  to  "The    Nature  of    Animal  Intelligence   and   the 

Methods  of  Investigating  It,"  Psych.  Rev.,  Vol.  VI,  p.  412. 
* Animal  Intelligence,  Psych.  Rev.,  Monograph  Supp.,  Vol.  II, 

No.  4,  pp.  62;    1898. 
The  Mental  Life  of  the  Monkeys,  Psych.  Rev.,  Monograph 

Supp.,  Vol.  Ill,  No.  5,  pp.  42;   1901. 
*TuRNER,  C.  H.    The  Homing  of  Ants :    An  Experimental  Study  of 

Ant  Behavior,  Jr.    Comp.  Neu.  6^  Psych.,  Vol.    XVII,  pp. 

367-434- 


TYPES   OF   ANIMAL   BEHAVIOR  9I 

Washburn,  M.  F.,  and  Bentley,  I.  M.  The  Establishment  of  an 
Association  Involving  Color  Discrimination  in  the  Creek  Chub, 
Jr.  Comp.  Neu.  6"  Psych.,  Vol.  XVI,  p.  113. 

* The  Animal  Mind,  Chapters  III  to  IX. 

♦Watson,  J.  B.,  1903.  Animal  Education,  Univ.  of  Chicago  Contri- 
butions to  Philosophy,  Vol.  IV,  No.  2. 

KiniESthetic  and  Organic  Sensations:  their  Role  in  the  Reac- 
tions of  the  White  Rat  to  the  Maze,  Monog.  Sup  pi.,  Vol.  8,  No.  2. 

Yerkes,  R.  M.  Inhibition  and  Reenforcement  of  Reaction  in  the 
Frog  Rana  Clamitans,  Jr.  Comp.  Neu.  &=  Psych.,  Vol.  XIV,  pp. 
124-137. 

Space  Perception  of  Tortoises,  Jr.  Comp.  Neu.  6^  Psych.,  Vol. 

XIV,  pp.  17-26. 

1903.  The  Instincts,  Habits,  and  Reactions  of  the  Frog,  Har- 
vard Psych.  Studies,  Vol.  I,  pp.  579-638;  Psych.  Rev.,  Mono- 
graph Supp.,  Vol.  IV. 

The  Sense  of  Hearing  in  Frogs,  Jr.  Comp.  Neu.  6r*  Psych.,  Vol. 

XV,  pp.  279-304. 

* Behavior  of  Roger,  Century,  February,  1908. 

The  Dancing  Mouse. 

Bohn's  Studies  in  Animal  Behavior,  Jr.  Comp.  Neu.  £r»  Psych., 

Vol.  XVI,  p.  231. 


CHAPTER   IV 

COMPLEX   BEHAVIOR   CHARACTERISTIC   OF    SPECIES 
—  INSTINCTS 

NATURE    AND    DIFFERENTIATION    OF   INSTINCTS 

Animals  belonging  to  the  same  species  have  certain 
characteristic  modes  of  behavior,  just  as  every  plant  and 
every  chemical  element  has  characteristics  distinguishing 
it  from  all  others.  These  modes  of  behavior  are  closely, 
related  to  bodily  structure  and  physiological  processes.' 
They  are  the  modes  of  behavior  that  have  usually  brought 
favorable  results  to  the  species  living  its  life  in  a  certain 
kind  of  environment.  In  the  lower  organisms  which  live 
in  a  fairly  constant  environment,  have  few  highly  special- 
ized sensory  motor  organs,  and  perpetuate  their  species  by 
division  or  budding,  instinctive  behavior  has  not  been 
clearly  differentiated  from  physiological  processes.  In 
creatures,  however,  that  react  in  response  to  suggestive 
stimuli  there  is  generally  a  clear  distinction  between  physio- 
logical processes  going  on  within  the  organism  and  behavior 
in  relation  to  the  stimulating  environment.  All  behavior 
that  is  favorable  to  the  survival  of  the  individual  or  its 
species,  and  is  called  forth  by  a  stimulus  that  does  not  of 
itself  materially  modify  the  physiological  processes,  may  be 
considered  as  belonging  to  the  instinctive  rather  than  to  the 
physiological  type  of  activity.  Where  the  reaction  is  of  a 
part  of  the  organism  only,  it  is  more  properly  called  a  reflex ; 

92 


COMPLEX  BEHAVIOR  CHARACTERISTIC  OF  SPECIES        93 

while  more  complex  reactions  of  many  parts  for  the  good 
of  the  whole  organism  are  designated  as  instincts.  In  the 
lower  organisms  reactions  are  largely  reflex,  while  in  higher 
animals  instincts  become  more  and  more  prominent. 

In  so  far  as  all  animals  have  common  ends  to  be  gained, 
the  modes  of  behavior  by  which  those  ends  are  reached 
may  be  regarded  as  belonging  to  the  same  type  of  instinct, 
whether  found  in  an  amaba  or  in  man.  In  instinctive 
development,  as  in  other  lines  of  development,  there  are 
in  the  higher  animals  specializations  and  additions  to  the 
simpler  instinctive  actions  shown  by  the  lower. 

FUNDAMENTAL    FORMS    OF    INSTINCTIVE    BEHAVIOR 

I.  Where  the  immediate  result  favors  the  preservation 
of  the  individual  reacting,  and  only  indirectly  the  preserva- 
tion of  the  species,  the  instinctive  action  is  Individualistic 
or  Self-Preservative.  This  form  of  behavior  is  specialized 
in  the  higher  animals  chiefly  into  three  kinds  of  activities : 
those  connected  first,  with  securing  food;  second,  avoiding 
danger;  and  third,  fighting  enemies  and  rivals.  The  acts 
accomplishing  these  ends  are  different  for  each  species  and 
of  all  degrees  of  complexity. 

The  individualistic  instinct  of  securing  food  is  always 
closely  correlated  with  structure  and  surroundings.  To  an 
expert  naturalist  a  single  organ,  bone,  or  tooth  of  an  animal 
may  give  an  unmistakable  indication  of  the  general  charac- 
ter of  its  feeding  instinct.  He  knows  whether  it  be  a  vege- 
table or  flesh-eater  and  can  form  some  idea  of  the  action 
by  means  of  which  it  secures  its  food. 

The    same  close  relation  of    instinct  and  structure  is 


94  GENETIC   PSYCHOLOGY 

shown  in  the  actions  of  avoiding  and  combating  enemies. 
The  instinct  to  remain  motionless  in  the  presence  of  a  pos- 
sible enemy  could  have  been  established  only  in  those  par- 
tridges whose  feathers  resemble  their  surroundings,  for  all 
others  would  be  likely  to  be  destroyed  if  they  remained  still 
in  the  presence  of  an  enemy  that  can  see.  To  escape  an 
enemy  depending  on  other  senses  than  sight,  the  partridge 
must,  however,  also  have  strong  wings  and  the  instinct  to 
use  them  effectively.  The  hedgehog  and  porcupine  have 
structures  that  make  fear  an  almost  useless  instinct  to  them, 
and  so  they  are  as  a  rule  very  bold.  Creatures  that  have 
no  means  of  defense  or  flight,  by  which  enemies  may  be 
escaped,  are  sometimes  enabled  to  survive  because  of  their 
resemblance  in  form,  color,  or  sound-producing  qualities, 
to  some  fierce  creature,  while  beasts  of  prey,  with  efficient 
fighting  apparatus,  have  sufficient  means  of  survival  with- 
out hiding  or  fleeing,  though  concealment  may  be  helpful 
in  capturing  prey  ;  hence  most  of  them  have  coloring 
corresponding  to  their  usual  surroundings. 

At  first  thought,  the  fighting  of  rivals,  which  are  of  course 
of  the  same  species,  does  not  seem  to  favor  the  survival 
of  the  species  even  indirectly,  but  a  little  reflection  shows 
that  such  action  eliminates  weaker  individuals  and  favors 
propagation  by  the  stronger.  This  instinct  is  most  promi- 
nent in  animals  living  in  groups,  under  conditions  in  which 
the  weaker  members  of  the  species  are  protected  from  de- 
struction by  being  associated  with  the  others.  In  such 
animals  it  is  necessary  that  there  should  be  fighting  among 
themselves  and  that  the  stronger  should  dominate,  in  order 
that  the  species  may  not  be  weakened  in  its  struggle  for 
existence  with  other  species. 


COMPLEX  BEHAVIOR  CHARACTERISTIC  OF  SPECIES     95 

Instincts  change  with  temporary  changes  in  structure 
and  physiological  states  at  different  ages,  at  different  times 
of  the  year,  and  because  of  hunger,  sickness,  or  wounds. 
Hence  there  is  great  variability  in  the  reactions  of  feeding, 
fighting,  and  escaping  danger  at  different  seasons  and  on 
account  of  special  physiological  conditions  of  the  individual 
animal. 

II.  A  mode  of  behavior  that  is  of  no  advantage  to  the 
individual  but  favors  the  production  of  other  individuals 
and  the  preservation  of  the  species,  is  known  as  the  Parental 
or  Racial  Instinct.  In  all  animals  reproducing  sexually, 
this  instinct  is  differentiated  from  purely  physiological 
processes.  In  some  animals,  however,  especially  insects, 
the  production  of  eggs  and  the  provision  made  for  their 
development  are  sometimes,  as  in  the  case  of  plants, 
only  a  slightly  differentiated  phase  of  the  physiological 
processes.  The  nest  and  egg  productions  of  insects  differ 
from  the  formation  of  fruit  cases  and  seed  by  plants, 
chiefly  in  the  fact  that  the  results  are  attained  by  move- 
ments that  are  rapid  enough  to  be  seen,  instead  of  by  slow 
growth  processes. 

The  care  of  the  young,  while  they  are  developing  into 
adults,  is  a  higher  form  of  the  parental  instinct,  which  is 
necessarily  more  prominent  in  proportion  as  the  number 
of  young  produced  is  small.  The  salmon  producing 
a  million  eggs  does  not  as  a  species  need  the  caretaking 
instinct  of  the  robin,  which  lays  only  a  half  dozen  or  so  eggs 
in  a  season. 

In  the  lower  vertebrates  the  sex  instinct  is  part  of  the 
time  absent,  while  at  other  times  it  completely  dominates 
behavior.     In  birds  and  mammals  the  instinct  is  stronji 


96  GENETIC   PSYCHOLOGY 

at  certain  times  of  the  year  but  usually  not  to  the  entire 
exclusion  of  the  individualistic  instinct. 

In  higher  animals  and  in  man  this  instinct  is  manifested 
in  a  great  variety  of  forms.  When  it  is  dominant,  many 
varieties  of  sensitiveness  and  movement  are  shown  in 
connection  with  securing  mates,  preparing  for  the  young, 
and  feeding  and  defending  them.  Acts  of  adornment, 
singing,  courage,  and  cunning  are  all  specializations  of 
behavior  correlated  with  and  more  or  less  closely  dependent 
upon  the  sex  instinct  and  the  physiological  specialization 
in  structure  of  the  two  sexes. 

For  all  species  of  animals  the  care-taking  form  of  this 
instinct  is  very  accurately  adjusted,  not  only  to  the  structure 
of  the  species  and  to  the  conditions  of  life,  but  also  to  the 
structure  and  behavior  of  the  young  at  birth  and  at  differ- 
ent stages  of  development.  Any  failure  of  adjustment 
would  be  disastrous  ;  for  example,  a  hen  could  not  rear 
young  robins  because,  no  matter  how  much  food  she  might 
find,  they  would  starve  if  it  were  not  placed  in  their  mouths; 
while  on  the  other  hand,  if  chickens  were  kept  in  a  nest 
and  fed  by  robins  they  would  fail  to  develop  properly 
because  of  lack  of  exercise.  In  the  torrid  zone  the  eggs 
and  young  are  sometimes  not  brooded  at  all,  while  in  the 
antarctic  region  the  penguin,  living  on  snow  and  ice,  holds 
its  one  egg  between  the  thighs  so  that  it  cannot  touch  the 
ice;  and  although  six  weeks  are  required  for  the  egg  to 
hatch  and  a  long  period  of  care  of  the  young  chick  follows, 
yet  natural  selection  in  that  environment  has  made  the 
instinct  of  brooding  so  strong,  that  all  the  birds  compete 
for  the  chance,  and  as  soon  as  one  drops  the  egg  or  chick 
another  takes  it. 


COMPLEX  BEHAVIOR  CHARACTERISTIC  OF  SPECIES     97 

III.  One  effective  means  of  survival  for  a  species  is 
that  of  living  together  in  groups  that  cooperate  to  a  greater 
or  less  extent  in  the  struggle  for  existence.  Modes  of 
behavior  concerned  with  such  group  life  constitute  the 
Social  Instinct.  In  social  insects,  such  as  bees  and  ants, 
this  instinct  dominates  all  their  behavior  so  that  most  of 
their  actions  are  adapted  to  the  preservation  of  the  group 
to  which  they  belong,  regardless  of  what  may  happen  to 
other  groups  or  to  themselves  as  individuals.  They 
cooperate  in  producing  and  caring  for  the  young  of  their 
colony  and  in  fighting  enemies,  whether  of  their  own  or  of 
another  species.  In  order  that  they  may  do  this  there 
is  often  considerable  specialization  in  structure,  fitting  the 
different  members  of  the  group  to  perform  their  part  in  the 
life  of  the  colony.  The  cooperation  is  not  so  much  that  of 
individuals  with  each  other  as  it  is  of  the  different  classes; 
e.g.  warriors  and  Workers  among  ants.  Individuals  are 
apparently  recognized  as  friends  or  enemies,  not  so  much 
by  their  individual  peculiarity  as  by  their  colony  odor. 
Any  individual  from  another  colony,  or  even  from  the  same 
colony,  if  it  has  been  with  those  of  another  colony  long 
enough  to  get  their  odor,  is  likely  to  be  treated  as  an  enemy. 

In  the  case  of  higher  animals  that  go  in  groups,  such  as 
geese,  wolves,  wild  cattle,  and  horses,  there  is  not  such 
marked  differentiation  of  structure  and  coo])eration  in  be- 
havior of  different  classes,  though  the  two  sexes  act  differ- 
ently and  the  stronger  individuals  take  the  part  of  leaders 
and  fighters.  In  such  animals  there  is  often  a  wonderful 
sensitiveness  to  the  action  of  companions  and  response  to 
such  actions  by  correlated  mo\-emcnt.  This  is  most  evi- 
dent in  following  leaders,  and  in  responding  by  appropriate 

H 


98  GENETIC   PSYCHOLOGY 

movements  to  special  cries  of  companions,  indicative  of 
food,  danger,  fighting,  or  pursuing. 

Social  action  is  also  sho\^•n  in  the  arrangement  of  a  group 
in  the  presence  of  danger  so  that  the  helpless  will  be  pro- 
tected, and  in  the  movements  of  a  pack  by  means  of  which 
prey  is  surrounded  and  captured.  Wolves  often  cooperate 
in  a  wonderful  way  till  their  prey  is  captured,  when  the 
individualistic  instinct  resumes  full  sway  and  they  fight  for 
possession  of  the  prey  that  they  have  cooperated  with  each 
other  in  securing.  Other  instances  of  social  behavior  of 
animals,  such  as  when  different  members  of  a  group  act 
successively  as  sentinels  while  others  feed  or  sleep,  depend 
upon  conditions  and  suggestions  that  are  imperceptible 
to  man. 

All  animals  that  live  successfully  in  groups  must  be  sensi- 
tive to  what  companions  are  doing  and  have  instinctive 
modes  of  responding  to  the  usual  behavior  of  other  mem- 
bers of  the  group.  This  characteristic  is  shown  in  a 
marked  degree  in  the  dog  as  compared  with  the  individual- 
istic cat.  The  cat  is  perhaps  no  less  intelligent,  learning  as 
readily  as  the  dog  when  rewarded  or  punished  in  a  way  that 
appeals  to  touch  or  taste,  but  it  is  not  so  much  affected  by  the 
tone  of  voice  or  expression  of  face  of  the  master.  The  dog, 
on  the  other  hand,  is  wonderfully  responsive,  not  only  to  the 
actions  of  other  dogs,  but  to  those  of  persons  and  to  the  tones 
and  facial  expressions  of  his  master.  His  original  social  in- 
stinct, that  rendered  him  sensitive  to  the  actions  of  com- 
panions in  the  chase,  has  been  specialized  during  his  long 
domestication  by  artificial  selection  and  breeding,  into 
sensitiveness  to  the  voice  and  movements  of  human  beings. 
In  individual  dogs  and  horses  this  sensitiveness  may  be 


COMPLEX  BEHAVIOR  CHARACTERISTIC  OF  SPECIES      99 

developed  so  as  to  become  equal  in  some  lines  to  that  of 
human  beings. 

In  children  not  only  is  there  great  sensitiveness  to  the 
tones  of  voice  and  movements  of  other  persons  but  also  a 
strong  tendency  to  act  so  as  to  attract  notice  and  get  ap- 
proval. Dogs  show  this  also,  but  in  the  human  species 
it  has  an  extraordinary  development,  appearing  in  various 
forms,  such  as  sympathy  and  ambition. 

These  three  most  fundamental  specializations  in  the 
behavior  of  all  but  the  lowest  animals.  Individualistic, 
Parental,  and  Social,  are  not  found  simultaneously  and 
equally  prominent  in  any  one  species,  except  in  a  few  that 
approach  man  in  complexity  of  organization.  Usually 
in  the  lower  forms  of  animals  one  of  these  instincts  only  is 
dominant  part  or  all  of  their  lives.  In  higher  animals, 
however,  they  may  all  be  prominent  at  the  same  time  and 
either  support  or  oppose  each  other.  This  is  one  reason 
why  their  behavior  is  often  so  difficult  to  predict  or  even 
explain.  The  instinct  that  has  been  dominant  may  at  any 
moment  gi\'e  way  to  another,  and  the  individual  thus  seems 
to  be  transformed  into  a  creature  with  a  different  nature  ; 
e.g.  in  the  mating  season  the  ordinarily  timid  deer  may 
savagely  attack  man.  The  other  reason  is  that  individual 
experience  and  habit  have  modified  the  behavior  of  indi- 
viduals in  such  a  way  tliat  a  knowledge  of  the  history  of  the 
individual  as  well  as  familiarity  with  the  characteristics  of 
the  species  is  necessary  in  order  to  interpret  the  behavior. 

Besides  the  most  distinctly  marked  forms  of  instinctive 
behavior  already  described  there  are,  in  the  higher  animals 
and  in  man,  many  others  specialized  from  and  correlated 
with  these  three.  One  group  of  these  may  be  designated  as 


lOO  GENETIC    PSYCHOLOGY 

Adaptive  instincts,  because  their  functions  seem  to  be  to 
adapt  the  individual  while  young  and  plastic  to  modes  of 
life  that  will  secure  survival  in  maturity.  They  are  also 
of  help  to  adult  individuals  in  making  quick  adjustments 
of  behavior  to  new  conditions. 

Play,  the  first  of  these,  is  useful  as  a  mere  outlet  of  sur- 
plus energy,  because  it  results  in  many  and  varied  move- 
ments, which  not  only  increase  the  strength  of  the  organism 
but  give  opportunity  for  many  movements  that  have  fa^•or- 
able  results  to  be  selected  for  repetition  and  development 
into  useful  habits.  This  holds  true  even  if  we  suppose  the 
character  of  the  movement  made  in  play  to  be  entirely  a 
matter  of  chance.  There  is,  however,  good  reason  for 
saying  that  the  playful  movements  of  young  animals  are 
not  wholly  a  matter  of  chance,  as  are  some  of  the  undiffer- 
entiated m.ovements  of  the  spontaneous  type. 

The  movements  made  in  play  are,  in  general,  charac- 
teristic of  the  species,  and  at  different  ages  are  specialized 
in  certain  directions  in  accordance  with  growth  and  devel- 
opment. Being  under  the  protection  of  their  parents  the 
young  animals  have  no  need  or  opportunity  to  stalk  prey, 
flee  from  danger,  or  fight  enemies;  but  as  the  organs  for 
performing  these  actions  develop,  energy  flows  out  in  play- 
ful movements  of  these  types.  The  young  animal  thus 
develops  powers  and  forms  habits  that  will  be  useful  in 
adult  life,  much  more  rapidly  than  he  would  if  his  move- 
ments were  of  an  entirely  random  character.  The  higher 
forms  of  playful  activity,  as  we  shall  see  later,  may  be 
developed  and  specialized  in  many  directions  and  to  a 
greater  extent  than  is  demanded  by  the  necessities  of  phys- 
ical survival. 


COMPLKX   Hi:iI.\\l()R  CHARACTICRISTIC  OF  SPICC'IES     lor 

The  instinct  of  'nuilnlioii  is  another  form  of  the  a(hi];ti\e 
instinct  which  hcli)s  in  ac(|uiring  useful  modes  of  beliavior 
and  saves  much  time  that  would  otherwise  be  spent  in 
useless  trial  movements.  Imitation  may  be  regarded  as  a 
specialization  of  the  social  instinct  that  renders  an  indi- 
vidual sensitive  to  what  companions  do  to  such  an  extent 
that  their  movements  serve  as  a  stimulus  to  make  similar 
movements.  An  animal  thus  sensitive  does  not  need  to 
wait  until  he  receives  clearly  and  strongly  the  stimulus 
suggestive  of  food  or  danger,  but  may  do  at  once  what  his 
companions  who  have  received  the  stimulus  are  already 
doing.  All  the  higher  animals  that  live  in  groups  are  aided 
in  escaping  danger  and  securing  food  in  this  way.  Young 
animals  therefore  learn  to  do  what  they  will  need  to  do  as 
adults  more  readily  when  surrounded  by  companions 
than  when  alone.  Men  having  the  same  instincts  are 
strongly  affected  by  the  movements  and  sounds  of  com- 
panions, especially  those  of  emotional  expression. 

Imitation  in  man,  however,  is  not  confined  to  emotional 
reactions  and  the  performance  of  instinctive  acts  under  the 
stimulus  of  their  performance  by  companions,  but  new 
movements  are  also  imitated  and  thus  learned.  Whether 
animals  thus  imitate  movements  made  in  their  presence  is 
as  yet  a  subject  of  experiment  and  debate ;  but  it  is  per- 
fectly clear  that  even  the  highest  animals,  other  than  man, 
do  not  perceive  and  imitate  to  any  considerable  extent 
movements  other  than  of  the  instincti\e  type.  In  children, 
on  the  other  hand,  the  instinct  is  so  strong  as  to  form  a 
marked  feature  of  their  playful  activities  and  to  be  one  of 
the  most  important  means  of  learning  how  to  reach  de- 
sired ends. 


102  GENETIC    PSYCHOLOGY 

Curiosity,  the  third  form  of  the  adaptive  instinct,  is 
the  result  of  special  sensitiveness  to  new  things,  and  is 
shown  primarily  in  a  tendency  to  approach  and  examine 
anything  new  in  the  environment.  It  is  social  only  in 
that  it  is  often  concerned  with  what  companions  are  doing 
as  well  as  with  changes  in  the  material  environment. 

In  origin  it  is  probably  most  closely  associated  with  the 
individualistic  instinct  of  fear,  since  fear  reactions  are  most 
frequently  called  forth  by  what  is  strange  and  unfamiliar. 
An  animal  governed  wholly  by  the  fear  impulse  would 
avoid  all  new  things  and  could  not  become  adapted  to  new 
conditions.  Curiosity,  like  an  antagonistic  muscle,  impels 
the  animal  to  examine  the  new  thing  that  fear  prompts 
him  to  run  away  from.  The  two  tendencies  are  clearly 
shown  in  the  behavior  of  a  young  puppy  who  alternately 
jumps  at  and  runs  away  from  a  new  object.  An  animal 
with  curiosity  soon  learns  not  to  run  away  from  harmless 
things  and  often  finds  ways  of  utilizing  them.  Even  as 
low  an  animal  as  the  starfish  explores  new  surroundings 
in  a  way  suggestive  of  the  curious  survey  of  new  surround- 
ings by  man.  Clearly,  then,  curiosity  is  of  great  advantage 
in  adapting  an  animal  to  changes  in  environment.  In  man 
this  instinct  has  similar  and  more  extensive  uses,  and  it 
also  develops  in  a  marked  degree  in  playful  forms  that  are 
of  great  significance  to  his  mental  life. 

SPECIALIZATION    OF    INSTINCTS 

The  constructive  and  collecting  instincts  are  specializa- 
tions of  the  nest-building  and  food-providing  form  of  the 
parental  instinct.     In  the  case  of  insects  and  birds  the 


COMPLEX  BEHAVIOR  CIIARiVCTERISTIC  OF  SPECIES     103 

constructions  arc  made  with  wonderful  skill  and  are  as 
useful  and  as  characteristic  of  each  species  as  is  their 
bodily  structure.  Some  mammals  show  a  good  deal  of 
skill,  notably  the  beaver,  which  also  seems  to  cooperate 
with  others  in  its  constructions.  Some  animals,  especially 
foxes  and  crows,  collect  material  of  all  kinds.  This  be- 
havior is  apparently  an  extension  in  the  form  of  play  of 
the  food-gathering  and  nest-constructing  instinct,  and  is 
closely  associated  with  ownership  and  with  rivalry. 

In  man,  with  motor  organs  capable  of  an  infinite  variety 
of  combinations,  the  constructive  instinct  has  had  a  wonder- 
ful development,  but  not,  as  in  the  case  of  animals,  toward 
any  particular  kind  of  structure  characteristic  of  the  spe- 
cies. The  constructions  of  the  spider,  the  bee,  the  robin, 
and  the  beaver  are  closely  related  to,  and  the  natural 
outcome  of,  their  structure  and  physiological  processes, 
Man's  motor  mechanism,  working  in  no  fixed  way  but 
by  varying  combinations  in  a  variety  of  ways,  naturally 
fails  to  produce  any  one  kind  of  structure  rather  than 
another,  except  perhaps  that  what  he  constructs  is,  like 
himself,  usually  bilaterally  symmetrical.  Each  individual 
man  has  the  general  instinct,  but  must  learn  what  to  con- 
struct and  how,  while  individual  animals  instinctively 
construct  as  those  of  their  species  have  always  done,  with 
little  or  no  learning  from  the  example  of  their  companions. 
In  man,  both  the  constructive  and  the  collecting  instinct 
take  more  or  less  playful  forms  and  develop  in  many  ways 
not  demanded  by  the  necessity  for  physical  survival. 

The  toilet-making  instinct  and  the  (Esthetic  instinct  are 
probably  in  part  extensions  of  the  constructive  and  col- 
lecting instincts,  and  also  correlated  with  certain  forms  of 


I04  GENETIC   PSYCHOLOGY 

the  individualistic,  sexual,  and  social  instincts.  The  toilet- 
making  instinct  is  very  prominent  in  many  animals,  espe- 
cially birds  and  the  individualistic  cat,  and  in  its  funda- 
mental form  it  is  undoubtedly  useful  in  preserving  the  health 
of  the  individual,  while  incidentally  it  favors  a  harmonious 
group  life. 

The  (Esthetic  instinct  may  or  may  not  be  present  in  any 
animal  below  man,  but  in  him  it  has  an  extraordinary 
power.  A  human  lover  of  bird  songs  can  scarcely  resist 
the  impression  that  a  song  bird  is  exercising  his  aesthetic 
sense  in  making  his  melodies  and  that  other  birds  must  be 
affected  aesthetically  by  them,  while  the  artist  has  much 
the  same  feelings  regarding  the  beauty  of  form  and  move- 
ment in  bird  and  butterfly.  Experiments,  however,  show 
that  the  selection  of  mates  is  not  affected  by  changing  the 
color  of  the  wings  of  butterflies ;  hence  it  is  not  likely  that 
the  aesthetic  sense  is  very  prominent  in  these  creatures 
and  it  is  practically  certain  that  it  plays  no  part  in  the 
selection  of  mates  and  the  development  of  certain  types  of 
coloring,  as  Darwin  supposed  it  did.  The  same  is  prob- 
ably true  in  the  main  of  birds  and  mammals.  The  bril- 
liant coloring  that  has  been  supposed  to  play  an  important 
part  in  the  mating  of  animals  is  perhaps  better  explained  as 
being  due  to  the  overflow  of  energy  not  used  in  reproduc- 
tion, which  modifies  certain  physiological  processes  and 
sensory-motor  activities  so  as  to  produce  bright  colors 
with  beauty  of  form  and  grace  of  movement. 

In  man  the  esthetic  instinct  has  played  an  important 
part  in  mental  development  and  in  history.  It  is  one  of 
the  most  striking  examples  of  an  instinct  developed  beyond 
the  necessities  of  physical  survival  and  to  an  extent  that 


COMPLEX  BEHAVIOR  CHARACTERISTIC  OF  SPECHIS     105 

makes  it,  in  many  instances,  stronger  than  the  desire  for 
food  or  the  fear  of  danger. 

There  are  many  tendencies  to  action,  sometimes  called 
instincts,  whose  origin  is  not  easily  traced  to  any  one  form 
of  useful  behavior,  among  which  are  teasing  and  jealousy. 
Leadership,  teasing,  and  jealousy  are  all  closely  related  to 
each  other  and  have  perhaps  originated  in  connection  with 
fighting  and  with  certain  forms  of  the  social  instinct. 

In  social  animals  the  individual  whose  actions  impress 
others  of  his  group  most  effectively  is,  to  a  greater  or  less 
extent,  a  director  of  group  behavior  and  has  what  may  be 
called  the  instinct  of  leadership.  An  individual  who  is 
sensitive  to  the  behavior  of  others,  especially  to  that  of  a 
leader,  is  by  instinct  a  follower.  Where  a  leader  acts  so  as 
to  direct  the  behavior  of  another  without  purpose  other  than 
to  direct  his  actions,  the  act  is  a  playful  manifestation  of 
the  instinct  of  leadership,  which  may  take  the  form  of 
teasing  or  bullying. 

Teasing  may  be  looked  upon  as  a  mild  and  playful  form 
of  fighting.  Any  creature  that  is  sensitive  to  what  his 
companions  do  and  shows  that  sensitiveness  in  his  reac- 
tions, is  subject  to  teasing.  Practical  jokes  and  humor  in 
all  its  forms  may  be  looked  upon  as  still  more  refined, 
intellectual,  and  human  forms  of  the  teasing  instinct,  which 
in  its  essential  nature  impels  one  creature  to  make  another 
do  useless  things. 

Jealousy  is  closely  related  to  the  susceptibility  to  teasing, 
for  an  individual  who  is  jealous  must  be  sensitive  to  the 
behavior  of  other  individuals.  Any  change  in  the  behavior 
of  a  companion,  especially  a  leader,  so  that  the  action  is 
directed  toward  some  other  in(li\i(lual,  arouses  jealousy. 


Io6  GENETIC   PSYCHOLOGY 

This  is  manifested  in  the  form  of  avoidance  of  the  formerly 
attractive  companion  or  perhaps  in  an  attack  upon  him  or 
his  new  follower.  In  human  beings,  jealousy  may  appear 
in  the  form  of  ideas  and  feelings  without  objective  action. 

The  expressive  instinct  is  a  special  form  of  the  social 
instinct  which  leads  animals  to  make  sounds  indicating 
their  own  bodily  or  mental  states  and  the  general  character 
of  the  stimuli  they  are  receiving,  in  such  a  way  that  other 
animals  may  respond  by  appropriate  movement.  Al- 
though the  expressive  instinct  is  generally  used  to  influence 
the  action  of  companions  it  may  also  be  used  to  frighten 
enemies  belonging  to  another  species.  In  animals,  the 
expressive  instinct  is  not  a  means  of  conveying  ideas  but 
only  of  suggesting  situations.  In  man,  whose  mental  life 
is  of  greater  importance  than  the  physical,  appropriate 
reaction  to  the  mental  states  of  others  is  continually  neces- 
sary, and  the  expressive  instinct  is  very  highly  developed. 
The  instinctive  sounds  and  gestures  which  he  is  able  to 
make  are  not  sufficient  to  meet  his  psychical  needs,  hence 
he  has  evolved  a  language  consisting  of  arbitrary  oral  and 
written  symbols. 

Man  not  only  expresses  himself  in  this  way  but  also  by 
artistic  creations  of  all  kinds.  In  art  and  literature  the 
expressive,  constructive,  and  aesthetic  instincts  blend,  and 
the  varieties  of  activity  resulting  have  no  possible  explana- 
tion in  the  necessities  of  the  physical  organism  but  only  in 
the  psychical  needs  of  man. 

The  regulative  instinct  manifested  in  moral  and  reli- 
gious behavior  is  complex  in  its  origin  and  perhaps  takes 
distinct  form  only  in  human  individuals  after  certain  kinds 
of  personal  experience.     Regulation  of  behavior  for  the 


COMPLEX  BEHAVIOR  CHARACTERISTIC  OF  SPECIES     107 

present  good  of  the  organism  is,  as  we  have  seen,  charac- 
teristic of  all  organisms,  but  regulation  of  present  behavior, 
so  that  it  will  harmonize  favorably  with  the  behavior  of  the 
individual  at  other  times,  is  a  more  complex  matter. 

A  bird  whose  instincts,  including  the  acts  of  mating,  nest- 
building,  sitting  on  the  eggs,  and  caring  for  the  young,  are 
dominant  in  normal  order,  has  the  acts  of  one  day  har- 
monized with  those  of  another.  A  disturbance  of  the  re- 
sults of  one  day's  action,  by  the  destruction  of  the  nest  or 
otherwise,  may  cause  the  cycle  to  begin  again  or  may  send 
it  into  the  next  stage,  as  of  gathering  food,  which  may  be 
given  to  a  mate  or  to  other  young.  It  is  not  likely  that  a 
bird  foresees  the  end,  and  the  relation  of  each  action  to  its 
attainment,  but  it  reacts  to  the  situation  in  a  sensory-motor 
way  according  to  the  dominant  instinct.  It  cannot  regu- 
late activity  outside  of  lines  of  behavior  characteristic  of 
its  species.  In  man,  however,  actions  are  regulated  partly 
by  ideas  of  the  end  to  be  gained  instead  of  exclusively  by 
sensory-motor  stimulation  and  blind  instinct;  hence  the 
regulative  instinct  plays  a  prominent  part  in  his  life. 

The  impulse  and  the  idea  giving  rise  to  religious  action 
are  closely  related  to  the  instinct  of  fear.  Fear  is  espe- 
cially aroused  by  the  unknown  and  the  strange,  and  is 
greatest  when  the  stimulus  is  not  perceived  but  only  sug- 
gested, particularly  when  companions  are  acting  as  if  there 
were  a  cause  of  fear.  No  panic  of  fear  among  animals  or 
men  is  so  great  as  that  due  to  an  unknown  cause  and  vio- 
lently reacted  to  by  some  individuals  of  the  group.  This 
reaction  to  the  unknown  is  the  fundamental  basis  of  the 
religious  impulse.  Natural  phenomena  suggesting  un- 
seen beings  may  arouse  the  tendency  to  react  to  what  is 


Io8  GENETIC   PSYCHOLOGY 

not  present,  but  the  impulse  is  much  stronger  when  other 
people  react  with  reference  to  such  a  being  or  force, 
whether  or  not  there  is  any  natural  phenomenon  suggest- 
ing its  presence.  The  memory  of  beings  to  whom  one 
has  reacted  but  who  are  not  now  present  may  also  arouse 
the  religious  impulses,  as  is  clearly  shown  in  ancestor  wor- 
ship. In  all  its  various  forms  religious  behavior  is  directed 
by  stimuli  suggesting  the  unknown  and  the  intangible. 
Those  who  are  sensitive  to  such  stimuli  and  have  their 
actions  directed  by  them  are  religious,  whatever  the  form 
of  their  actions  and  beliefs,  while  those  not  thus  sensitive 
are  lacking  in  the  religious  instinct. 

Moral  behavior  is  more  completely  social  in  its  character, 
and  the  social  animals  perhaps  show  the  rudiments  of  moral 
behavior.  The  dog  that  responds  to  the  movements  and 
cries  of  others  of  the  pack  so  as  to  cooperate  in  capturing 
the  prey,  is  practicing  canine  morality.  His  action  is 
regulated,  not  by  the  stimulation  of  things,  but  by  the 
actions  of  companions.  This  is  the  essence  of  morality 
in  animal  and  man,  —  that  his  actions  shall  be  directed  by 
the  same  principle  of  action  as  those  of  his  companions. 
A  dog  that  gives  a  false  call  on  a  chase,  or  fails  to  respond 
to  the  signal  "close  in,"  is  not  a  favorite  with  his  fellows 
any  more  than  the  man  who  tells  untruths  and  does  not  act 
according  to  the  "rules  of  the  game." 

Desire  for  approbation  and  fear  of  punishment  enforce 
the  tendency  to  moral  actions,  while  the  imitative  tendency 
helps  to  direct  it  in  accordance  with  example  and  custom. 
In  the  absence  of  companions  action  may  be  directed  along 
moral  lines,  either  by  memory  of  how  other  people  act  or 
by  habit.     A  human  being  who  had  never  had  companions 


COMPLEX  BEHAVIOR  CHARACTERISTIC  OF  SPECIES     109 

could  not  be  moral,  though  he  might  be  religious  to  some 
extent.  In  moral  behavior  there  is  no  necessary  sugges- 
tion of  a  Being  with  reference  to  whom  customs  have  been 
formed,  while  in  religious  behavior  there  is  always  such 
suggestion. 

REFERENCES 

Angell.     Psychology,  Chapter  XV. 

Baldwin,    J.    M.     Social    and    Ethical   Interpretations,  Chapters 

IV,  IX,  X,  XI. 
*BuRKE,  F.  S.     Teasing  and  Bullying,  Ped.  Sent.,  Vol.  IV,  pp.  336- 

371- 
*Chadbourne,  p.  a.     Instinct. 
Courtis,  S.     Response  of  Toads  to  Sound  Stimuli,  Am.  Natur.,  1907, 

Vol.  XLI,  pp.  677-682. 
Delbceuf.     Affections  and  Jealousies  of  Lizards,  Pop.  Sci.  Mo., 

Vol.  L,  pp.  395-399- 
Forrel.     Ants   and   Some   of   their   Instincts,  Monisl,  Vol.  XIV, 

PP-  33-36  and  177-194- 

Ants  and  Some  Other  Insects. 

♦French,  F.  C.      Group  Self-Consciousness,  Psych.  Rev.,  Vol.  XV, 

pp.  197-200. 
*Gesell,  Arnold  L.      Jealousy,  Am.  Jr.  Psych.,  Vol.  XVII,  pp. 

437-496. 
*Groos,  K.     The  Play  of  Animals. 

The  Play  of  Man. 

*Hall  and  Smith.     Showing  off  and  Bashfulness  as  Phases  of  Self- 
Consciousness,  Ped.  Sem.,  Vol.  X,  pp.  159-199. 
Reactions  to  Light  and  Darkness,  Am.  Jr.  Psych.,  Vol.  XIV, 

pp.  21-83. 
*Hall,  G.  S.     a  Study  of  Fear,  Ayn.  Jr.  Psych.,  Vol.  VIII,  pp. 

147-249. 

Adolescence,  Chapter  XV. 

*Herrick,  C.  L.     The  Beginnings  of  Social  Reaction  in  Man  and 

Lower   Animals,  Jr.   Com  p.   Neti.  &-=■  Psych.,  Vol.   XIV,   pp. 

118-123. 


no  GENETIC    PSYCHOLOGY 

*Herrick,  C.  L.     The  Relation  of  Instinct  to  Intelligence  in  Birds, 

Science,  Vol.  XXVII,  1908,  pp.  847-850. 
*H0BH0USE,  L.  T.     Mind  in  Evolution,  Chapter  IV. 
♦James.     Psychology,  Chapter  XXV. 
Jones,  J.  W.  L.     Sociality  and  Sympathy,  Psych.  Rev.,  Monograph 

Supp.,  Vol.  V,  No.  I,  whole  No.  18. 
KiRKPATRiCK.   Fundamentals  of  Child  Study,  Chapters  IV,  VI,  VII, 

VIII,  IX,  X,  XI,  XII. 
Kline,  L.  W.     The  Migratory  Instinct  vs.  Love  of  Home,  Am.  Jr. 

Psych.,  Vol.  X,  pp.  1-8 1. 
LoEB.     Physiology  of  the  Brain,  Chapter  XIII. 
Lubbock.     Ants,  Bees,  and  Wasps. 
Marshall,  H.  R.     Instinct  and  Reason. 
Mills,  W.     Animal  Intelligence,  Part  II. 
♦Morgan,  C.  L.     Animal  Life  and  Intelligence,  Chapter  XI. 

* Comparative  Psychology,  Chapter  XII. 

Peckham,  G.  W.,  and  E.  G.     Wasps,  Social  and  Solitary. 

♦Robinson,  Louis.     Wild  Traits  in  Tame  Animals. 

Romanes.     Mental  Evolution  in  Animals,  Chapters  XI,  XII,  XIII, 

XIV,  XV,  XVI,  XVII. 

Animal  Intelligence. 

Terman,  L.  W.     a  Preliminary  Study  in  the  Psychology  and  Peda- 
gogy of  Leadership,  Fed.  Sent.,  Vol.  XI,  pp.  413-451. 
♦Thorndike.     Elements  of  Psychology,  Chapter  XII. 
♦Wasman.     Psychology  of  Ants  and  Higher  Animals. 
♦Wheeler,  W.  M.     The  Origin  of  Slavery  Among  Ants,  Pop.  Sci. 

Mo.,  Vol.  LXXI,  pp.  55c^559- 
Vestigial   Instincts  in   Insects  and  Other  Animals,  Am.  Jr. 

Psych.,  Vol.  XIX,  pp.  1-13. 
♦Wundt.     Human    and    Animal    Intelligence,  Chapters   XXVII, 

XXVIII. 


CHAPTER   V 

BEHAVIOR   OF   INDIVIDUALS— ACQUISITIONS   OF 
HABITS   AND    IDEAS 

HABIT  FORMATION 

Although  animals  of  the  same  species  have  common 
characteristics  of  behavior,  yet  the  individuals  differ  greatly. 
These  differences  are  due  in  part  to  variations  in  structure 
and  in  part  to  differences  in  surrounding  conditions  at  the 
moment,  as  well  as  to  the  continuing  effects  of  recent 
stimulation  which,  as  shown  in  the  chapter  on  types  of 
behavior,  may  modify  reactions  to  subsequent  stimuli. 
The  larger  portion  of  individual  difference  in  behavior  is, 
however,  to  be  accounted  for  by  more  or  less  permanent 
modification  of  individuals  by  the  reactions  they  have 
previously  made  to  their  environment. 

The  lines  of  distinction  between  changes  in  behavior 
produced  by  present  conditions,  the  continuing  effects  of 
recent  stimulation,  and  the  more  permanent  changes  known 
as  "habits"  are  not  easily  drawn.  The  experiments  of 
Hodge  upon  vorticella  furnish  a  typical  instance  of  per- 
sisting effects  that  have  been  interpreted  as  habit  forma- 
tion or  learning.  He  found  that  vorticella  that  had  been 
made  sick  by  yeast  refused  to  take  any  more  for  several 
hours.  In  this  case  the  effect  of  the  stimulus  was  rather 
prolonged,  but  there  is  no  evidence  that  the  creatures  be- 
haved differently  toward  yeast  after  the  immediate  efifects 


112  GENETIC    PSYCHOLOGY 

of  the  Stimulus  had  disappeared.  In  other  words,  it  was 
probably  not  really  a  case  of  permanent  modification  of 
physiological  activity  or  habit  formation. 

All  the  lower  organisms,  under  long-continued  exposure 
to  unusual  light  or  temperature  stimulation,  are  modified 
for  a  greater  or  less  time  by  the  experience.  When  trans- 
ferred back  to  the  former  medium  they  react  to  it  in  a  nega- 
tive way.  In  some  instances  the  change  that  may  thus  be 
produced  is  so  great  that  the  animal  can  live  in  a  medium 
which  would  have  been  destructive  if  it  had  not  been  grad- 
ually accustorhed  to  it,  and  a  sudden  transference  to  the 
medium  in  which  it  formerly  lived  may  cause  death.  Such 
instances  as  this  of  passive  accommodation  to  continued 
stimulation  are  on  the  border  line  between  the  temporary 
effects  of  stimulation  and  passive  habit  formation. 

In  higher  animals  there  is  often  what  seems  to  be 
passive  habit  formation  in  the  form  of  decreased  response 
to  sounds  and  other  suggestive  stimuli  that  are  not  in 
themselves  either  helpful  or  harmful  and  also  accommoda- 
tion to  harmful  stimuli  so  that  they  are  better  endured. 

In  the  case  of  the  starfish  experimented  upon  by  Jen- 
nings, where  the  animal  learned  to  use  a  hitherto  unused 
arm,  we  have  an  example  of  more  active  habit  formation. 
The  strength  of  the  hitherto  unused  arm  was  probably 
increased  by  the  exercise  so  that  it  took  the  lead  in  the 
righting  movement  in  place  of  the  previously  stronger 
and  more  active  arms.  All  cases  of  habit  formation 
probably  involve  a  decrease  in  some  kinds  of  activity 
and  an  increase  in  others.  The  parts  concerned  in  effect- 
ing the  right  movement  consequently  grow  in  strength  and 
determine  the  direction  of  future  activity.     In   passive 


BEHAVIOR   OF    INDIVIDUALS  II3 

accommodation  to  continuous  or  repeated  stimulation  the 
modifications  produced  are  mostly  in  the  direction  of 
minimizing  certain  activities;  while  in  positi\"e  reactions 
having  favorable  results  the  effect  is  due  more  to  increase 
in  acti\-ity  and  strengthening  of  the  parts  determining 
action. 

Behavior  that  appears  like  learning  has  recently  been 
rej)orted  by  vStevenson  Smith  in  an  animal  as  low  as  the 
Paramecium.  He  found  that,  when  confined  in  a  capillary 
tube  so  that  it  could  turn  upon  reaching  the  surface  film 
only  by  doubling  on  itself,  after  a  number  of  experiences, 
it  reacted  in  this  way  at  once  when  the  film  was  touched, 
without  the  usual  trial  movements  of  backing  and  starting 
forward  again. 

Evidence  of  persisting  modification  in  the  behavior  of 
a  sea  anemone  has  been  found  in  the  fact  that  after  repeated 
experience  of  taking,  swallowing,  and  ejecting  filter  paper 
soaked  in  meat  juice,  it  not  only  ceased  to  take  it  at  the 
time  but  after  several  days.  This  would  seem  to  be  a  real 
case  of  learning  or  habit  formation.  In  the  case  already 
mentioned  of  crabs  that  learned  to  go  to  a  certain  part  of 
the  aquarium  for  food  whenever  the  screen  was  inserted, 
we  have  a  still  clearer  example  of  habit  formation.  The 
screen  was  in  itself  neither  a  favorable  nor  an  unfavorable 
stimulation  but  became  suggestive  of  a  favorable  stimulus 
to  be  received.  This  is  typical  of  the  kind  of  habit  forma- 
tion found  in  higher  animals. 

It  should  be  noted  that  habits  are  not  formed  merely 
because  of  performing  and  repeating  an  act  in  a  certain 
way.  Whether  the  tendency  to  repeat  the  act  shall  be 
greater  or  less  is  determined  by  the  results  of  the  act.     If 


114  GENETIC   PSYCHOLOGY 

the  results  are  favorable,  the  tendency  to  repeat  the  act  is 
increased ;  but  if  the  results  are  unfavorable,  the  act  is  either 
performed  with  less  vigor  or  is  replaced  by  some  other 
act.  When  a  cat  jumps  on  a  table  and  gets  some  food, 
the  tendency  to  repeat  that  act  is  increased  because  of  the 
favorable  result ;  but  if  she  performs  the  same  movement 
of  jumping  on  the  table  and  gets  a  blow  on  the  head,  the 
tendency  to  jump  on  the  table  is  decreased.  Evidently 
the  activities  of  the  parts  concerned  in  behavior  are  modi- 
fied by  what  happens  after  a  movement  has  been  made. 
It  seems  probable,  therefore,  that  favorable  results  follow- 
ing any  movement  tend  to  increase  the  strength  of  the 
apparatus  concerned  in  directing  the  movement  and  the 
tendency  of  impulses  to  take  the  same  course,  while  un- 
favorable results  produce  opposite  effects. 

Since  most  animals  are  capable  of  variety  of  movement 
and  are  all  the  time  being  stimulated  in  several  ways,  and 
since  the  activity  of  one  part,  especially  in  the  higher 
animals,  affects  and  is  affected  by  the  activity  of  other 
parts,  habit  formation,  in  the  sense  of  learning  to  do  a 
specific  thing,  involves,  to  a  considerable  extent,  learning 
to  do  it  under  certain  conditions.  These  conditions  in- 
volve some  similarity  in  the  number,  kind,  and  intensity 
of  stimuli  being  received  and  their  relation  to  the  condition 
that  is  calling  forth  the  action  which  is  being  developed 
into  a  habit.  These  conditions  are  internal  and  physio- 
logical as  well  as  external.  In  order  that  a  habit  may  be 
quickly  formed  the  external  conditions  of  stimulation,  and 
such  internal  conditions  as  hunger,  and  presence  or  ab- 
sence of  fatigue,  etc.,  must  be  the  same.  If  under  these 
circumstances  the  results  are  each   time  favorable,   the 


BEHAVIOR   OF    INDIVIDUALS  II5 

reaction  that  brought  these  results  under  these  conditions 
is  quickly  established  as  a  habit. 

In  most  instances  of  active  habit  formation  in  the  higher 
animals,  which  are  affected  by  a  great  variety  of  stimula- 
tions and  whose  activities  are  all  closely  related,  the  ex- 
ternal and  internal  conditions  are  rarely  entirely  uniform. 
This  may  in  part  account  for  the  fact  that  in  habit  forma- 
tion in  the  higher  animals  the  reaction  to  a  situation  does 
not  immediately  become  uniform,  though  it  is  likely  to 
do  so  if  the  first  reaction  is  not  too  complex  and  has  im- 
mediately favorable  results.  As  we  have  already  seen, 
the  movements  first  made  in  a  given  situation,  as  for 
instance  in  trying  to  get  into  a  box  where  there  is  food, 
are  of  a  varied  or  trial  character.  If  success  is  attained, 
the  next  time  the  situation  is  presented  the  trial  movements 
are  fewer  in  number,  but  rarely  is  the  successful  movement 
immediately  performed.  As  the  situation  is  presented 
again  and  again  the  useless  movements  disappear,  success 
is  attained  in  a  shorter  time,  and  usually  the  movements 
then  become  uniform;  but  uniformity  may  be  disturbed 
either  by  changes  in  the  external  conditions  or  by  unusual 
internal  conditions  such  as  hunger  or  fear. 

Where  the  result  of  a  series  of  movements  is  unfavorable, 
we  have  similarly  the  dropping  out  of  useless  movements ; 
only  in  this  case  it  is  the  movements  nearest  the  unfavorable 
result  that  are  dropped  out  first  instead  of,  as  in  the  other 
case,  the  movements  farthest  removed  from  the  favorable 
result.  This  is  well  illustrated  by  Morgan's  experiments 
with  chickens.  When  a  furry  and  disagreeable  caterpillar 
was  thrown  into  the  pen  a  chicken  ran  to  it,  picked  it 
up,  dropped  it,  wiped  its  bill,  then  turned  away.     When 


Il6  GENETIC   PSYCHOLOGY 

another  caterpillar  was  thrown  in  the  chicken  ran  to  it  but 
did  not  pick  it  up,  wiped  its  bill,  and  turned  away.  Later 
the  wiping  of  the  bill  was  omitted,  and  finally  the  chicken 
did  not  go  to  the  caterpillars  when  they  were  thrown  in. 

So  far  as  observed,  this  elimination  of  useless  movements 
in  learning  is  very  rare  in  the  lower  animals.  As  previ- 
ously described,  the  stentor  goes  through  its  series  of 
varied  reactions  in  response  to  a  continued  unfavorable 
stimulus  again  and  again,  but  apparently  without  learning 
to  eliminate  any  of  the  ineffective  movements.  Preyer 
thought  he  observed  some  shortening  in  the  time  required 
by  a  starfish;  after  repeated  experience,  to  remove  a  cover- 
ing that  he  placed  on  one  of  its  arms,  also  in  the  time 
required  to  get  away  when  the  animal  was  pinned  down ; 
but  Jennings  finds  no  evidence  that  starfish  eliminate 
useless  movements  and  select  for  repetition  the  ones  that 
bring  success.  The  varied  but  often  ununified  movements 
possible  to  the  starfish  may  be  one  reason  for  this.  One 
of  the  lowest  animals  that  has  thus  far  been  observed 
to  learn  to  take  a  more  direct  course  to  an  end  is  the  crab 
in  simple  maze  tests. 

In  man  the  formation  of  habits  conforms  to  the  same 
general  principles  as  in  animals.  In  learning,  useless 
movements  are  sometimes  slowly  eliminated  and  some- 
times rapidly.  This  applies  not  only  to  movements  but 
also  to  thinking,  as  when  one  is  trying  to  solve  a  puzzle 
or  a  proposition  in  geometry.  In  some  instances,  so  far 
as  external  behavior  is  concerned,  there  are  no  useless 
movements  to  be  eliminated,  the  act  being  at  once  per- 
formed in  the  shortest  way.  In  such  cases,  however, 
if  the  situation  is  a  new  one,  there  is  probably  a  formation 


BEHAVIOR    OF    INDIVIDUALS  it; 

of  trial  ideas,  and  wlien  llic  right  one  has  been  found  it 
is  selected  and  the  movement  executed.  This  is  often 
the  case  when  a  person  attempts  to  undo  a  fastening  or 
to  solve  a  puzzle.  Children,  like  animals  in  such  circum- 
stances, are  likely  to  make  trial  movements,  while  adults 
with  experience  in  doing  such  things,  refrain  from  move- 
ment until  they  have  solved  the  puzzle  either  by  means 
of  trial  images  or  by  some  process  of  reasoning. 

It  is  not  to  be  understood  that  the  most  economical 
mode  of  reaching  favorable  results  is  necessarily  acquired 
before  the  reaction  becomes  established  as  a  habit.  If 
a  series  of  movements  has  favorable  results  more  quickly 
than  any  other  series  of  movements  that  has  been  tried, 
it  may  become  established  as  a  habit,  although  it  is  far 
from  the  shortest  and  most  economical  mode  of  securing 
the  result.  It  is  not  true  therefore  that  practice  neces- 
sarily makes  perfect.  Practice  may  just  as  readily  es- 
tablish an  imperfect  and  uneconomical  mode  of  reaching 
an  end.  This  is  an  important  principle  to  be  recognized 
by  teachers,  who  should  be  satisfied  as  long  as  a  pupil  is 
changing  for  the  better  in  anything  he  is  doing,  but  should 
take  care  that  he  does  not  form  a  fixed  habit  before  a 
reasonable  degree  of  perfection  has  been  attained. 

In  animals  such  as  the  turtle  and  the  guinea  jjig,  which 
are  not  inclined  to  make  many  or  varied  movements,  any 
reaction  that  is  successful  may  quickly  become  established 
as  a  habit  without  any  shortening  or  elimination  of  useless 
movements.  Although  variety  of  movement  may  not 
always  be  favorable  to  rapid  learning  of  a  particular  thing, 
yet  it  may  prevent  too  early  formation  of  habits  of  doing 
things   in   imperfect   and   uneconomical   ways.     .•\  young 


Il8  GENETIC   PSYCHOLOGY 

cat  or  rat  does  not  usually  drop  useless  movements  as 
quickly  after  his  first  success  as  older  ones  do,  but  if  there 
are  several  ways  of  succeeding  he  may  find  one  more 
economical  than  that  first  learned.  Too  early  fixing  of 
habits  in  human  beings  is  unfavorable  to  progress  and 
to  originality. 

After  any  form  of  reaction  has  been  established  as  a 
habit  it  is  likely  to  persist,  even  if  the  creature  is  in  some 
way  induced  to  make  a  reaction  that  more  quickly  brings 
more  favorable  results.  If,  however,  the  results  of  a 
habitual  reaction  are  artificially  made  unfavorable  and 
especially  if  at  the  same  time  conditions  are  changed  so 
as  to  call  forth  varied  reaction,  an  old  habit  may  be  broken 
up  and  a  new  and  better  one  formed.  It  is  reasonable 
to  suppose  that  every  habit  has  a  cause,  but  only  in  the 
case  of  habits  recently  formed  will  removal  of  the  cause 
quickly  eliminate  the  habit. 

As  we  have  already  seen,  the  instincts  of  animals  are 
determined  by  natural  selection  acting  during  the  life  and 
development  of  the  species.  We  shall  now  see  that  there 
is  a  principle  of  selection  concerned  in  the  development 
of  habits  in  the  individual.  Natural  selection  is  effective 
because  of  the  death  of  individuals  having  uneconomical 
modes  of  behavior  and  the  consequent  elimination  of  such 
behavior  from  the  species.  In  the  development  of  the 
individual,  modes  of  behavior  are  selected  because  of 
their  favorable  results,  while  those  having  unfavorable 
or  less  favorable  results  are  eliminated.  Neither  the 
creature  as  a  whole  nor  any  part  of  it  is  destroyed ;  but  the 
apparatus  concerned  in  bringing  favorable  results  is 
strengthened  for  that  mode  of  activity,  while  that  bringing 


BEHAVIOR   OF    INDIVIDUALS  II9 

unfavorable  results  is  relatively  weakened.  In  this  way, 
in  the  individual,  modes  of  behavior  that  have  most  favor- 
able results  are  selected  for  survival  and  developed  into 
habits. 

COMPLICATIONS    OF    INSTINCTS    AND   HABITS 

A  creature  with  no  instinctive  tendency  toward  any 
particular  form  of  movement,  but  with  only  the  general 
tendency  to  react  under  certain  conditions  by  varied  trial 
movements,  would  have  its  behavior  determined  wholly 
by  environment.  If  it  were  capable  of  retaining  the 
effects  of  past  experience  its  habits  would  depend  entirely 
upon  its  own  individual  history.  As  a  matter  of  fact, 
however,  all  creatures  that  retain  in  any  considerable 
degree  the  effects  of  past  experience  are  also  endowed 
with  some  useful  types  of  reaction,  and  hence  their  move- 
ments are  not  of  an  entirely  trial  character.  Their  first 
reactions,  and  consequently  many  of  their  habits,  are  there- 
fore in  part  the  result  of  instinctive  modes  of  behavior 
dependent  upon  native  structure. 

The  first  reaction  of  an  individual  in  a  new  situation  is 
usually  neither  wholly  of  a  trial  character  nor  specifically 
determined  by  the  instincts  of  the  species,  though  the 
general  character  of  its  behavior  is  determined  by  an 
instinctive  tendency  to  a  certain  type  of  reaction.  Subse- 
quently, individual  experiences  in  which  results  are  favorable 
or  unfavorable  serve  to  increase  certain  instinctive  reactions, 
to  check  the  development  of  others,  and,  still  more  fre- 
quently, to  refine  and  specialize  them  and  to  associate 
them  with  suggestive  stimuli. 

Experimenters  note  great  differences  in  the  readiness 


I20  GENETIC   PSYCHOLOGY 

with  which  any  particular  kind  of  modification  of  behavior 
may  be  produced,  depending  upon  whether  it  (i)  calls 
only  for  a  specialization  in  a  mode  of  action  instinctive  to 
the  animal,  (2)  involves  the  inhibition  of  instinctive  re- 
action, or  (3)  requires  the  development  of  a  mode  of  be- 
havior new  to  the  species.  The  instinctive  snapping  of 
a  fish  at  almost  any  small  object  appearing  in  his  neigh- 
borhood is  not  readily  inhibited  by  want  of  success  or 
even  by  injurious  pricks.  Even  though  there  is  temporary 
inhibition  the  reaction  is  likely  to  be  made  again  after  an 
interval,  as  is  well  illustrated  by  the  experiments  of  Mobius 
upon  a  pike,  Triplett  upon  a  perch,  and  Washburn  and 
Bentley  upon  a  chub.  In  every  case  the  fish  was  a  long 
time  learning  not  to  react  to  a  useless  or  even  injurious 
stimulus,  and  when  some  time  had  elapsed  after  an  interval 
of  practice,  it  would  again  dart  at  the  object,  especially 
when  it  appeared  suddenly. 

When  two  stimuli,  as  red  and  green  objects,  were  pre- 
sented at  once  to  the  chub,  one  of  which  meant  food  and 
the  other  not,  the  learning  was  much  more  rapid  because 
the  instinct  of  darting  at  an  object  need  not  be  inhibited 
but  only  specialized  into  darting  at  the  red  instead  of  the 
green  object. 

The  more  definite  and  reflexlike  an  instinct,  the  more 
difficult  it  is  to  produce  permanent  modification,  and  es- 
pecially to  produce  inhibition  of  the  act.  On  the  other 
hand,  a  less  definite  and  permanent  instinct,  such  as  that 
of  following  moving  objects,  shown  by  chickens  and  sheep, 
may  readily  be  inhibited  by  painful  results. 

It  is  more  difficult  to  teach  a  cat  to  retrieve  objects 
thrown  into  the  water  than  it  is  a  dog,  because  a  cat  in- 


BEHAVIOR    OF    1NI)I\IDUALS  121 

slincti\"c'ly  draws  away  from  the  water,  while  most  clogs 
do  not.  It  is  a  very  difficult  task  to  teach  a  pig  to  walk 
on  a  very  narrow  path,  such  as  the  edge  of  a  board,  be- 
cause its  instinct  is  to  avoid  such  paths.  It  is  less  diffi- 
cult to  teach  this  trick  to  a  dog,  while  cats  and  monkeys 
learn  it  without  teaching. 

A  new  movement,  like  that  of  walking  on  the  front  feet, 
is  difficult  to  teach  to  either  dogs  or  monkeys,  not  so  much 
because  there  is  an  instinct  opposing  this  movement  as  be- 
cause there  is  no  instinct  favoring  it.  For  a  similar  reason 
Berry  found  it  hard  to  teach  rats  to  pull  a  string  with  the 
paw  rather  than  with  the  teeth,  although  cats  readily 
learn  this  movement.  Most  of  the  training  of  animals  by 
showmen  and  much  of  that  given  by  scientific  experi- 
menters with  higher  animals,  involve  at  the  same  time 
special  increase  in  response  to  one  stimulus  and  decrease 
to  others.  When  Thorndike  fed  monkeys  when  he  put 
bread  in  his  left  hand  and  did  not  feed  them  when  he  put 
it  in  his  right,  they  had  to  learn  both  to  respond  to  one 
stimulus  and  to  inhibit  the  tendency  to  respond  to  the 
other.  The  same  is  true  when  any  specific  signal,  such 
as  a  form  or  color,  is  given  as  a  preliminary  to  feeding,  in 
such  a  way  that  the  specific  stimulus  and  not  the  total 
situation  means  food.  Such  experiments  also  in\-olve 
specialized  discrimination  which  may,  by  careful  training, 
be  refined  almost  to  the  j^hysiological  limit. 

The  development  of  specific  reactions  into  habits  is 
influenced  by  the  nature  and  order  of  the  external  stimu- 
lation, by  the  favorable  or  unfavorable  results  of  reaction, 
and  by  the  general  instinctive  tendencies  of  the  creature. 
If  these  were  the  only  influences  determining  the  develop- 


122  GENETIC    PSYCHOLOGY 

mcnt  of  a  habit,  practice  in  performing  the  act  could  only 
be  obtained  when  the  external  conditions  were  repeated 
wholly  or  in  part,  and  the  development  of  any  particular 
reaction  into  a  habit  would  be  very  slow.  There  is,  how- 
ever, a  general  neural  tendency  to  continue  or  repeat  any 
activity,  and  for  nervous  impulses  to  readily  pass  out 
along  channels  that  have  just  been  taken  by  other 
nervous  impulses.  Because  of  this,  reactions  are  fre- 
quently repeated  after  the  external  stimulus  has  ceased. 
This  is  illustrated  by  the  fact  that  infants  when  in  the 
"da-da  and  bla-bla"  stage  often  repeat  several  times 
any  sound  or  movement  that  they  have  made.  It  is  espe- 
cially likely  to  occur  when  the  movements  produce  a  stimu- 
lus similar  to  the  one  starting  the  reaction,  as  is  the  case 
in  imitating  a  sound  that  has  been  heard.  The  name 
"circular  reaction"  has  been  given  by  Baldwin  to  this 
phenomenon,  and  it  is  properly  regarded  as  an  important 
factor  in  hastening  the  development  of  habits  and  as  a  basis 
of  imitative  acts.  The  phenomenon  is  found  in  all  animals, 
from  the  lowest  to  the  highest,  and  in  the  highest  type  of 
mental  activity.  A  child  is  likely  to  work  a  problem  in  the 
same  way  in  which  he  has  just  worked  another  problem, 
even  though  it  may  be  of  a  different  kind,  and  a  scientist  is 
likely  to  apply  the  same  theory  to  a  great  variety  of  facts. 
When  an  animal  is  becoming  adapted  to  many  phases 
of  a  complex  and  frequently  changing  environment, 
the  method  of  trial  movements,  even  though  facilitated 
somewhat  by  the  fact  that  chance  is  partially  eliminated 
by  native  structure  and  instinctive  tendencies,  would  not 
be  sufficiently  effective  even  though  habit  formation  is 
hastened  by  spontaneous  repetition.     He  needs  something 


BEHAVIOR   OF   INDIVIDUALS  123 

that  will  cause  him  to  develop  the  power  to  make  effective 
reactions  to  situations  before  those  situations  occur  at  a 
time  when  they  in\olve  immediate  and  serious  conse- 
quences. This  is  especially  needed  by  all  of  the  higher 
animals  and  man.  They  arc  aided  in  preparing  to  meet 
future  situations  by  the  play  instinct,  which  causes  any 
surplus  energy  to  flow  out,  not  only  in  random  movements, 
but  in  kinds  of  movements  often  made  in  the  instinctive 
reactions  of  the  species.  In  this  way  the  organs  for  such 
movements  are  strengthened  by  abundant  exercise  and 
there  is  much  greater  likelihood  of  the  right  reaction  being 
made  when  the  situations  are  first  seriously  met. 

Even  this,  however,  is  not  sufi'icicnt  to  always  insure 
proper  reactions  to  the  en^•ironment  if  reactions  could 
be  learned  only  by  the  individual's  own  exj^erience.  It 
is  of  great  ad\-antage  to  a  creature  if  he  can  jjrofit  by  the 
individual  experiences  of  others  of  his  species.  This  is  pro- 
vided for  to  some  extent  in  the  higher  animals,  and  in  a  very 
marked  degree  in  man,  by  the  imitative  tendency.  A 
creature  that  imitates  must  not  only  be  responsive  to  the 
objects  in  his  environment  but  must  be  especially  sensitive 
to  what  his  companions  are  doing.  j\Iany  animals  are 
thus  sensitive,  so  that  they  respond  to  the  mo\ements  and 
cries  of  their  companions  that  have  percci\ed  an  enemy 
or  food  without  waiting  until  they  themselves  perceive  it. 
In  this  form  of  the  imitative  tendency  the  animal  makes 
no  movements  new  to  his  species,  or,  in  other  words,  no 
movement  that  is  not  to  some  extent  instinctive ;  but  he 
begins  such  mo\'ements  in  response  to  his  perception  of 
them  as  made  by  companions,  instead  of  in  response  to 
the  stimulus  that  has  excited  them. 


124  GENETIC    PSYCHOLOGY 

In  man  wc  have  an  imitative  tendency  of  a  somewhat 
different  kind.  He  is  so  sensitive  to  what  companions 
do  that  he  not  only  docs  what  they  do  when  the  actions 
are  of  the  usual  type,  but  he  is  so  affected  by  movements 
which  he  perceives,  that  he  reproduces  them,  although 
they  are  entirely  new.  This  kind  of  imitation  is  possible 
in  man,  (i)  because  of  the  greater  development  of  the 
social  instinct  which  makes  him  more  sensitive  than  other 
animals  to  what  companions  are  doing,  (2)  because  of 
the  character  of  his  motor  apparatus  which  may  be  ad- 
justed in  an  infinite  variety  of  ways,  and  (3)  because  he 
possesses  nerve  centers  that  can  readily  acquire  the  power 
to  make  these  adjustments.  A  child  is  often  able,  without 
any  preliminary  practice,  to  imitate  simple  sounds  and 
gestures  with  considerable  accuracy.  In  other  cases  a 
movement  or  sound  crudely  like  that  which  has  been  per- 
ceived is  produced  and  repeated  with  variations  until  it 
is  made  with  accuracy.  When  a  child  yawns,  coughs, 
cries,  smiles,  frowns,  or  performs  any  other  reflex,  expres- 
sive, or  instinctive  movement  when  he  perceives  some  one 
else  perform  it,  his  imitation  is  not  different  from  that 
of  the  higher  animals,  but  when  he  makes  a  movement 
that  is  not  instinctive  in  character,  such  as  waving  his 
hand  or  playing  pat-a-cake  or  uttering  a  word  when  he 
perceives  some  one  else  do  it,  he  is  engaged  in  a  kind  of 
imitation  that  is  exceedingly  rare,  if  not  utterly  impossible, 
in  nearly  all  species  of  animals. 

The  exceedingly  varied  character  of  imitati\'e  acts  that 
can  be  performed  by  children  makes  it  difficult  to  explain 
them  as  due  wholly  to  inherited  structure  and  even  more 
difficult   to   explain   them   as   originating   wholly   in   the 


BEHAVIOR   OF    INDIVIDUALS  125 

previous  experience  of  tlie  indi\idual.  The  extraordinary 
facility  with  which  children  sometimes  reproduce  sounds 
which  they  hear,  often,  without  practice,  rivaling  the 
accuracy  of  the  j)honograi)h,  indicates  that  there  must 
be  a  close  relation  between  the  centers  for  sound  percep- 
tions and  the  centers  controlling  the  movement  of  the 
vocal  organs.  The  facility  with  which  gestures  are  imi- 
tated indicates  that  the  visual  centers  are  related  to 
the  centers  controlling  arm  movements.  If  it  were  en- 
tirely a  matter  of  chance  as  to  what  movement  should 
be  made  in  response  to  the  sound  of  the  letter  "a,"  it 
would  take  a  lifetime  of  experience  in  which  this  sound 
was  continually  being  heard  and  some  kind  of  res[)onse 
given,  before  the  sound  would  be  uttered.  On  the  other 
hand,  we  cannot  suppose  that  the  apparatus  concerned 
in  the  perception  of  the  letter  "a"  and  the  apparatus 
concerned  in  its  utterance  are  definitely  connected  at  birth 
in  such  a  way  that  the  sound  must  produce  the  correct 
movement.  It  must  be  however  that  imj)ulses  which 
are  at  first  wirlely  diffused,  spread  more  readily  from  the 
auditory  centers  to  the  centers  for  vocal  utterance  than  to 
any  other  part  of  the  brain,  and  that  the  spreading  of 
impulses  in  response  to  the  sound  "a"  is  slightly  differ- 
ent from  that  in  response  to  the  sound  "b."  The  imita- 
tive movement  is  therefore  at  first  partly  determined  and 
partly  of  a  trial  character  and  it  becomes  accurate  in  the 
same  way  as  do  other  reactions.  The  pleasure  of  imitat- 
ing what  has  been  perceived  hastens  the  process. 

The  possession  of  the  imitative  instinct  greatly  facili- 
tates the  learning  of  individual  cats,  dogs,  birds,  and 
horses  in  the  lines  of  their  instinctive  behavior,  as  is  shown 


126  GENETIC   PSYCHOLOGY 

by  the  fact  that  they  learn  much  more  rapidly  when  as- 
sociated with  companions.  In  the  case  of  children,  who 
have  so  much  to  learn  and  who  are  able  to  learn  not  only 
in  the  line  of  instinctive  movements  but  also  to  learn  all 
kinds  of  new  movements,  the  imitative  tendency  plays 
a  still  more  important  part.  A  human  being  without 
opportunity  to  imitate  companions  would  scarcely  be 
recognized  as  a  human  being.  It  is  largely  because  of 
his  great  power  of  imitation  that  man  is  able  to  acquire 
an  almost  infinitely  greater  variety  of  motor  skill  than 
any  other  animal. 

Imitation  is  especially  helpful  in  acquiring  complex 
movements,  the  elements  of  which  are  already  familiar, 
and  in  such  acquisitions  by  man,  nerve  centers  concerned 
in  the  formation  of  free  ideas  are  developed  and  play 
an  important  part  in  connecting  the  series  of  movements. 

FREE    IDEAS 

We  have  already  found  that  modifications  in  behavior 
may  be  produced  in  all  organisms.  In  the  lower  organisms 
they  are  usually  either  temporary  or  else  become  permanent 
only  by  a  sort  of  slow  growth  process.  In  the  higher 
organisms  the  modifications  are  much  more  rapid  and  more 
permanent.  Such  modifications  are  more  properly  de- 
scribed as  learning,  especially  when  the  activity  varies  in  the 
direction  of  eliminating  useless  movements  and  securing 
ends  in  a  more  economical  way.  In  the  higher  animals 
this  elimination  of  useless  movements  may  proceed  very 
rapidly.  If  all  but  the  essential  movements  are  omitted  at 
once  we  have  a  type  of  learning  common  in  men  but  rare 
in  animals. 


BEHAVIOR   OF   INDIVIDUALS  127 

Such  learning  seems  to  invoh'c  an  analysis  of  the  situation 
as  a  whole  and  a  reaction  to  the  essential  stimulus  only. 
It  is  claimed  that  such  a  mode  of  learning  is  possible  only  to 
a  creature  capable  of  forming  free  ideas  of  the  elements 
of  the  situation  and  reacting  to  them,  regardless  of  the 
other  elements  with  which  they  are  associated.  It  will 
be  admitted  that  most  of  the  behavior  of  most  animals  may 
be  explained  without  supposing  them  to  possess  such  free 
ideas.  The  instances  in  which  such  ideas  seem  needed  to 
explain  animal  behavior  are  few  and  may  have  occurred  by 
chance,  or  it  may  be  that  individual  animals,  either  because 
of  special  training  or  because  they  are  the  geniuses  of  their 
species,  are  able  to  form  some  free  images. 

In  objective  terms  the  question  involved  is  really  this. 
Is  there  an  apparatus  that  can  respond  to  the  essential 
elements  of  a  situation  after  a  single  experience  and  that 
can  be  aroused  to  activity  by  the  recurrence  of  the  essentials 
of  the  situation  in  connection  with  another  set  of  elements? 
It  will  be  much  more  convenient  however  in  discussing  this 
question  to  use  subjective  terms  and  to  speak  of  the  func- 
tioning of  such  a  specialized  apparatus  as  a  free  idea. 
We  shall  therefore  anticipate  later  discussion  of  con- 
sciousness and  not  only  use  subjective  terms  but  consider 
the  matter  from  the  standpoint  of  our  own  conscious 
experience. 

The  results  of  a  single  experience  that  seem  to  exist  in 
such  a  form  as  to  direct  subsequent  l)ehavior  may  take  the 
form  of  a  memory  image,  a  free  image  or  idea,  or  of  an 
anticipatory  or  perceptual  image.  IMost  persons  would 
probably  think  of  the  memory  image  as  first  in  the  order  of 
mental  genesis  and   the  anticipatory   image  as  the  last. 


128  GENETIC   PSYCHOLOGY 

If  by  memory  is  meant  simply  the  persistence  of  the  efTects 
of  a  former  stimulus  there  would  be  good  ground  for  this 
view,  but  if  memory  means,  as  it  usually  means  in  psychol- 
ogy, not  simply  the  reproduction  of  the  former  state,  but  a 
consciousness  that  this  mental  state  was  experienced  in 
another  situation  than  the  one  now  present,  this  view  is 
probably  exactly  the  reverse  of  the  true  one. 

It  is  a  well-known  fact  that  associations  are  more  effective 
in  the  same  direction  in  which  they  were  formed  than  they 
are  in  the  reverse  direction.  When  we  cannot  recall  the 
next  element  in  a  series,  whether  it  be  a  movement,  a  word, 
or  an  idea,  we  are  likely  to  begin  again  the  series,  hoping 
that  the  desired  and  anticipated  element  will  be  brought 
into  consciousness  by  the  repetition  of  those  that  preceded 
it.  In  the  case  of  partly  learned  quotations,  series  of 
movements,  or  steps  in  reasoning,  we  are  often  able  to  pro- 
ceed when  given  a  portion  of  a  series,  before  we  are  able  to 
give  the  series  independently  as  a  whole  or  any  one  element 
of  it  separately.  We  may  know  just  what  to  do,  say,  or 
think  when  started  on  the  series,  although  we  could  not  of 
ourselves  begin  the  series. 

In  cases  where  we  cannot  immediately  take  the  next  step 
and  hence  cannot  definitely  image  it,  we  may  still  know  its 
general  character  and  may  be  able  to  recognize  at  once 
whether  any  element  suggested  is  or  is  not  the  one  desired. 
This  ability  to  continue  a  series  indicates  some  kind  of  an 
anticipatory  idea  which  makes  us  know  when  the  right  thing 
is  presented,  but  it  does  not  mean  that  we  have  any  such 
idea  independent  of  the  series  calling  it  up,  and  still  less  does 
it  mean  that  we  have  a  genuine  reminiscent  memory  of  the 
element  in  some  other  situation  not  now  presented  to  us. 


BEHAVIOR   OF    INDIVIDUALS  129 

In  other  words,  the  order  of  development  in  consciousness 
is  first,  indefinite  antici])atory  images  of  the  general  char- 
acter of  what  is  to  come;  second,  more  definite  images 
when  the  series  or  situation  which  formerly  preceded  or 
accompanied  it  is  reproduced ;  third,  partially  free  images 
of  an  element  in  a  series  or  situation,  aroused  by  another 
scries  or  situation,  most  of  the  elements  of  which  are 
different;  fourth,  a  free  image  which  may  be  aroused  with- 
out any  direct  sensory  stimulation ;  and  fifth,  a  reminiscent 
or  memory  image  of  the  element  as  having  occurred  in 
another  situation  or  series. 

Not  only  does  a  study  of  our  own  mental  processes  lead  to 
this  view  of  the  case,  but  biological  principles  point  in  the 
same  direction.  It  is  relatively  of  little  importance  to  a 
creature  to  be  able  to  form  images  of  a  situation  formerly 
present.  The  essential  thing  is  to  be  able  to  act  in  such  a 
way  as  to  secure  favorable  results  now  and  in  the  future. 
This  means  that  the  action  is  to  be  guided  by  what  will 
happen  as  a  result  of  any  series  of  reactions.  If  the  situa- 
tion and  the  series  of  movements  begun  in  response  to  it 
suggest  an  unfavorable  result  to  follow  the  continuation  of 
the  series,  we  may  suppose  that  such  an  anticipatory  idea 
would  have  the  same  effect  in  the  way  of  decreasing  and 
inhibiting  action  as  was  formerly  produced  by  the  unfavor- 
able results  themselves.  An  anticipatory  idea  of  the  results 
to  follow  a  given  series  of  movements  would  therefore  serve 
the  very  useful  purpose  of  inhil^iling  movements  that  would 
bring  unfavorable  results,  and  of  insuring  and  increasing 
.  the  vigor  of  movements  that  would  bring  fa\-orable  results. 
Such  an  anticipatory  image  would  be  useful  even  if  the 
exact  nature  of  the  results  were  not  represented. 


130  GENETIC    PSYCHOLOGY 

Definite  memories  are  also  less  necessary  than  definite 
anticipatory  images.  The  choice  of  the  right  mode  of  ac- 
tion in  a  new  situation  may  often  be  made  without  definite 
memories  of  what  formerly  occurred  in  connection  with  the 
elements  determining  the  reaction.  If  these  elements  were 
greatly  emphasized  in  the  original  experience  they  may, 
so  far  as  consciousness  is  concerned,  constitute  about  all 
there  is  of  the  new  situation  and  may  suggest  at  once  the 
idea  of  the  result  without  any  consciousness  of  the  result 
as  having  been  experienced  in  another  situation;  e.g. 
an  object  that  has  caused  pain  may  be  shunned  in  an 
entirely  new  environment  without  a  definite  memory  of  the 
former  experience  and  surroundings.  As  we  have  already 
seen  in  the  case  of  the  starfish  righting  itself,  the  different 
parts  may  at  first  act  independently,  but  when  the  impulse 
to  turn  itself  over  appears,  the  action  of  each  part  is 
modified  in  such  a  way  as  to  bring  about  the  turning  by 
some  one  method.  In  a  similar  way  the  actions  of  all 
creatures  are  unified  and  correlated  by  the  end  to  be  ob- 
tained. It  is  natural  therefore  to  suppose  that  when 
consciousness  begins  to  play  a  part  in  the  direction  of  be- 
havior it  takes  the  form  of  an  anticipatory  idea  of  results 
to  be  secured,  which  helps  to  unify  and  direct  behavior 
in  accordance  with  results  of  past  experience.  Conscious- 
ness of  elements  to  be  combined  in  a  new  way  to  secure 
desirable  ends,  and  reminiscent  images  of  past  experi- 
ences, would  naturally  be  much  later  in  development  and 
useful  not  so  much  in  determining  the  general  character 
of  the  reaction  as  in  choosing  the  most  effective  means  of 
reaching  the  end. 

All  the  higher  animals  act  as  if  they  had  some  idea  of 


BEHAVIOR   OF    INDIVIDUALS 


131 


results,  and  nearly  all  students  of  animal  life  will  admit  that 
they  do  ha\e  such  ideas.  They  can  also  learn  to  recognize, 
with  great  accuracy,  specific  elements  in  a  situation,  to 
which  they  react.  Many  persons  do  this  without  forming 
images,  and  it  is  probable  that  animals  do.  When  they  do 
form  images  they  are  usually  aroused  by  a  sensory-motor 
series  that  has  previously  led  to  the  corresponding  ex- 
perience. 

Animals  do  not  readily  learn  the  elements  in  any  situa- 
tion unless  reacted  to  by  themselves.  Thorndikc  thought 
that  they  could  not  learn  in  any  other  way  than  by  their 
own  movements,  but  Cole  found  that  raccoons  were  helped 
to  learn  how  to  get  food  by  being  put  in  the  box  where  it 
was  to  be  obtained,  and  he  thought  that  they  got  the  idea 
of  how  to  get  the  food  by  this  experience.  He  also  found, 
as  some  other  experimenters  have,  that  putting  an  animal 
through  the  movements  helps  him  to  learn  a  series, 
although  he  does  not  learn  as  quickly  as  when  he  can  in 
some  way  be  induced  to  go  through  the  series  himself. 

In  order  that  free  ideas  may  be  formed,  elements  of  the 
whole  situation  and  the  corresponding  reaction  must  be 
selected,  and  then  these  elements  must  be  freed  from  their 
connection  with  any  one  series  or  situation.  The  fact 
noted  by  Davis  that  a  raccoon  was  almost  as  much  dis- 
concerted by  approaching  a  familiar  fastening  from  a  new 
direction  as  by  a  new  fastening,  indicates  that  an  animal's 
reaction  is  to  the  whole  situation  as  it  confronts  him.  He 
also  reports  a  striking  instance  in  which  one  of  the  raccoons 
studied  by  him  showed  little  evidence  of  analyzing  the 
situation,  and  learned  by  trial  instead  of  by  perception  of 
elements  and  relations.     After  the  raccoon  had  learned  to 


132 


GENETIC   PSYCHOLOGY 


open  a  door  fastened  with  a  bolt  on  the  left  side  of  the  door, 
the  bolt  was  removed  and  a  bear-down  lever  placed  on  the 
right  side.  The  raccoon  worked  for  a  long  time  where  the 
bolt  had  been,  trying  to  push  what  was  not  there.  After 
assuming  all  sorts  of  positions  he  accidentally  pushed  the 
lever  down  with  his  hind  foot,  which  slipped  off  the  corner 
of  the  box,  where  he  was  standing  with  his  head  down. 
He  opened  it  four  times  in  this  way,  then  his  foot  failing 
to  open  it  when  it  slipped,  he  turned  and  opened  it  with  his 
fore  paws.  The  next  day  he  assumed  the  upside  down 
position,  then  turned  and  used  the  fore  paws.  Later  he 
did  not  assume  that  position  but  still  put  his  hind  foot 
against  the  lever  before  pushing  with  the  fore  paws.  With 
further  practice  he  doubtless  could  have  learned  to  push  it 
with  one  front  paw  only.  Evidently  the  analysis  of  the 
whole  situation,  so  far  as  there  was  any,  corresponds 
closely  with  the  dropping  out  of  useless  movements  as  the 
more  favorable  mode  of  reaction  is  acquired.  It  is  probable 
that  the  process  of  analysis  of  situations  is,  as  in  this  case, 
always  closely  correlated  with  the  elimination  of  useless 
movements. 

The  importance  of  having  success  follow  the  right  move- 
ment in  learning  how  to  do  anything,  is  well  illustrated  by 
the  fact  that  after  a  raccoon  had  succeeded  a  few  times  in 
getting  a  door  open  by  pressing  down  a  lever,  in  one  case 
after  pressing  it  down  he  reversed  the  movement  and  thus 
brought  it  in  place  again  so  the  door  did  not  open.  The 
lever  was  fixed  by  the  experimenter  so  this  could  not  happen 
again,  but  not  until  after  about  fifty  trials  did  the  raccoon 
open  the  door  with  as  few  errors  as  before  his  failure  to  get 
the  door  open  by  the  right  movement.     The  negative  re- 


BEHAVIOR   OF    INDIVIDUALS  133 

suits  of  some  experimenters  may  perhaps  be  accounted 
for  in  this  way  as  well  as  the  lack  of  success  of  unappreci- 
ative  teachers  of  children. 

The  process  of  forming  free  ideas  by  both  men  and 
animals  involves  attention  to  the  elements  of  the  situation, 
and  reaction  to  those  elements  not  simply  as  a  part  of 
one  situation  leading  to  an  end  of  a  certain  kind,  but 
as  elements  in  a  variety  of  situations  leading  to  various 
ends.  A  free  idea  of  a  lever  and  its  characteristics, 
whatever  the  situation  and  the  end  to  be  gained,  is 
easily  acquired  by  man,  who  has  used  it  under  many  cir- 
cumstances and  for  different  ends ;  but  by  an  animal  that 
has  used  it  only  as  a  means  of  getting  food  under  certain 
conditions  such  an  idea  cannot  possibly  be  formed. 

A  monkey  observed  by  Hobhouse,  which  had  learned  to 
throw  a  cloth  over  an  object  that  it  could  not  reach,  and 
draw  it  nearer,  was  given  a  stick  to  use  for  the  same  pur- 
pose. By  drawing  the  attention  of  the  animal  to  the  stick 
by  moving  it,  the  animal  was  induced  to  take  it  and  to 
begin  scratching  around  with  it,  and  largely  by  accident  the 
object  was  thus  brought  within  reach.  After  a  time  the 
monkey  frequently  used  the  stick  to  get  things  that  it  could 
not  reach.  Previous  action  in  drawing  things  toward  it 
evidently  helped  m  learning  to  use  the  stick,  but  trial  move- 
ments rather  than  the  image  of  the  motion  to  be  made 
seemed  to  be  the  chief  factor  in  learning.  The  stick  had  a 
hook  on  the  end,  which  made  it  much  more  effective  if 
rightly  used ;  but  the  animal  did  not  seem  to  notice  this 
characteristic  of  the  tool,  and  there  was  little  or  no  evidence 
of  his  possessing  an  idea  of  the  movement  to  be  made  in 
order  to  use  the  stick  effectively. 


134  GENETIC   PSYCHOLOGY 

Attempts  to  teach  a  monkey  such  tricks  as  this  do  not 
usually  succeed,  seemingly  because  the  animal's  attention 
cannot  be  directed  to  the  exact  movements  made  by  his 
teacher.  He  may,  in  performing  the  act,  succeed  more 
quickly  by  having  his  attention  directed  to  the  object 
to  be  moved ;  but  he  is  not  likely  to  notice  specific  facts 
regarding  it,  such  as  in  just  what  direction  and  how  far  a 
fastening  must  be  moved  to  open  a  door.  He  gets  such 
knowledge  not  by  observing  another  animal  or  person  undo 
the  fastening  but  as  the  accidental  result  of  trial  move- 
ments, Watson,  after  a  long  series  of  attempts,  found  it 
impossible  to  teach  a  monkey  how  to  use  a  rake  or  perform 
any  other  movement  simply  by  seeing  him  or  a  companion 
perform  the  act.  This  lack  of  interest  and  attention  to  the 
exact  character  of  the  movements  made  by  persons  and 
companions  is  doubtless  the  reason  why  animals  learn 
little  that  is  new  by  imitation.  It  is  doubtful  if  they 
even  observe  the  exact  character  of  their  own  successful 
movements.  The  chief  help  that  they  get  from  seeing  acts 
performed  is  in  having  their  attention  directed  to  the  right 
place  or  object,  and  the  object  rather  than  the  movement 
is  apparently  the  center  of  interest.  Haggerty  has  recently 
made  the  interesting  observation  that  monkeys  imitate 
strange  monkeys  more  readily  than  companions.  This  is 
probably  because  they  watch  a  stranger  more  closely. 

Any  means  by  which  essential  elements  are  made  im- 
pressive so  that  they  determine  action  will  be  helpful 
in  the  first  stage  of  the  process  of  learning.  The  reaction 
once  acquired  may  be  specialized  to  almost  any  extent  by 
slight  variations  in  the  situation,  and  in  this  way  a  certain 
element  may  come  to  be  reacted  to  without  regard  to  its 


BEHAVIOR  OF   INDIVIDUALS  135 

surroundings;  e.g.  a  signal  given  in  a  certain  situation 
and  accompanied  by  various  gestures  and  followed  by  im- 
mediate reward  may  be  reacted  to  when  given  without  such 
accompaniments  and  in  a  form  scarcely  perceptible  to  a 
human  observer.  It  is  not  however  freed  in  this  way  from 
the  movement  made  nor  from  the  end  gained  by  the 
movement. 

After  the  essential  elements  in  the  situation  have  been 
learned  so  that  they  are  accurately  recognized,  they  are 
not  necessarily  known  as  separate  elements  but  as  the 
significant  portion  of  the  whole  situation  or  series.  The 
pigeon  may  learn  to  discriminate  a  square  as  a  means  of 
food  when  it  is  placed  on  one  of  several  vessels  in  a  cage 
and  always  has  food  under  it.  In  other  surroundings 
it  might  not  look  under  a  square  for  food.  The  location 
of  the  square  is  the  significant  element  in  the  whole  situa- 
tion and  there  is  not  necessarily  any  idea  of  the  square 
apart  from  the  situation  in  which  it  serves  as  a  food  signal. 
If  a  monkey  learned  to  use  a  rake,  but  only  for  getting  food 
outside  of  the  cage,  it  would  not  have  a  free  idea  of  a  rake 
but  would  know  it  only  as  a  part  of  a  certain  situation. 

Hobhouse  quotes  a  remarkable  instance  of  an  animal 
which  either  by  coincidence  or  because  of  unusual  intelli- 
gence used  a  reaction  learned  in  one  situation  to  meet 
quite  a  different  situation.  A  dog  had  learned,  when 
given  meat,  to  go  to  the  door  and  wait  for  it  to  be  opened 
that  he  might  go  out  and  eat  the  meat.  One  time, 
hearing  some  dogs  outside  that  he  evidently  wanted 
to  be  with,  he  picked  up  a  piece  of  bread  (which  he 
would  never  eat),  went  to  the  door,  and  waited  for  it 
to    be   opened.     The    immediate  object,    to   get   out  of 


136  GENETIC    PSYCHOLOGY 

doors,  was  the  same,  but  in  one  case  it  was  to  get  out 
of  doors  to  eat  the  meat,  and  in  the  other,  in  order  to 
join  some  other  dogs.  Also  the  article  used,  a  piece  of 
bread,  was  different  from  the  one  customarily  used  in  this 
act.  We  seem  therefore  to  have  a  case  of  the  essential 
element,  the  standing  before  the  door  with  something  in 
the  mouth,  selected  and  used  as  a  means  for  obtaining  re- 
sults that  were  only  partially  the  same  as  had  previously 
been  secured  by  this  reaction.  This  is  probably  as  strong 
evidence  of  the  possession  of  a  free  idea  as  has  been 
authentically  reported.  If  such  actions  were  usual  instead 
of  the  rare  thing  among  animals,  there  would  be  little 
ground  for  denying  that  they  do  possess  some  free  ideas. 
If  they  are  not  explained  as  the  result  of  chance  they  still 
serve  to  emphasize  the  fact  that  free  ideas  must  very  rarely 
be  possessed  by  animals,  otherwise  they  would  not  be 
considered  worth  describing.  An  infant  of  two  years  who 
would  do  such  a  thing  might  be  regarded  as  "bright"  and 
the  incident  related  to  friends ;  but  actions  of  this  character 
are  so  common  in  older  children  and  adults  as  not  to  be 
considered  worthy  of  notice. 

Such  incidents  as  that  of  the  dog  which  had  chased  a 
rabbit  into  a  drain  a  number  of  times  and  which  finally 
took  a  direct  course  to  the  mouth  of  the  drain  (instead  of 
following  the  roundabout  course  of  the  rabbit)  and  thus 
succeeded  in  catching  the  animal,  can  be  explained  much 
more  easily  on  simpler  principles  than  the  functioning  of 
free  ideas.  As  we  have  already  seen,  in  the  learning  stage 
of  habit  formation,  the  movements  are  not  the  same  each 
time  but  vary  in  the  direction  of  eliminating  useless  move- 
ments and  reaching  the  end  by  more  direct  means.     There 


BEHAVIOR   OF    INDIVIDUALS  137 

is  especially  likely  to  be  change  of  movements  when  those 
that  have  been  made  have  not  had  favorable  results.  The 
taking  of  the  more  direct  course  to  the  drain  where  the 
rabbit  had  frequently  been  smelled  was  therefore  of  the 
same  general  character  as  the  behavior  of  animals  in 
finding  their  way  through  a  maze.  There  is  no  reason  to 
suppose  that  free  ideas  play  a  part  in  such  instances  except 
when  the  change  takes  place  very  quickly. 

As  we  have  already  indicated,  man  is  endowed  with 
motor  apparatus  capable  of  being  adjusted  in  an  infinite 
variety  of  ways,  hence  he  can  manipulate  objects  freely  for 
various  purposes.  The  monkey,  which  is  the  most  facile 
of  animals  in  the  use  of  his  hands,  is  still  far  inferior  to  man, 
partly  because  he  cannot  use  his  thumb  in  opposition  to 
the  fingers.  In  general,  animals  that  are  capable  of  the 
greatest  variety  of  motor  adjustments  are  regarded  as  most 
intelligent.  This  is  probably  not  alone  because  the  ability 
to  make  a  variety  of  movements  makes  it  possible  for  them 
to  more  fully  express  their  mental  states,  but  because  the 
making  of  this  variety  of  movements  develops  the  mental 
states  indicated  by  them.  In  other  words,  mental  control 
in  the  form  of  free  ideas  is  developed  during  the  process 
of  gaining  varied  motor  control. 

We  have  also  found  that  man  possesses  a  greater  variety 
of  instincts  than  any  other  animal.  This  means  that  he 
has  a  greater  variety  of  ends  to  be  obtained,  or,  in  other 
words,  has  a  variety  of  interests.  The  use  of  a  certain 
object  or  movement,  not  only  in  new  situations  but  for 
entirely  different  ends,  is  the  most  effective  means  of  free- 
ing that  element  from  any  particular  series  or  situation  in 
which  it  has  occurred.     Very  rarely  does  an  animal  use  an 


138  GENETIC    PSYCHOLOGY 

object  or  a  movement  as  a  means  to  more  than  one  end. 
To  a  child  an  object  of  a  certain  shape  may  be  of  interest 
to  him  as  an  indication  of  food,  as  a  sign  of  the  direction  to 
be  taken  in  going  home,  as  an  object  to  be  used  in  play, 
etc.  With  such  experiences  as  these  it  cannot  be  to  him 
simply  an  element  in  some  one  situation,  but  it  comes  to 
have  a  significance  of  its  own,  and  he  can  form  an  idea  of 
it  to  be  used  in  new  situations  and  for  a  different  purpose. 
If  animals  could  react  in  a  sufficiently  varied  way  and  for  a 
sufficient  variety  of  ends,  it  is  not  improbable  that  they 
could  form  free  ideas  just  as  man  does  by  such  reactions. 
Perhaps  such  animals  as  the  monkey  and  the  elephant  may 
form  some  ideas  of  objects  distinct  from  any  particular  sur- 
roundings or  movements.  The  fact,  however,  that  they  are 
limited  in  their  ability  to  manipulate  objects  and  hence  in 
their  power  to  use  or  construct  tools,  that  they  have  no 
language  by  which  to  designate  objects  in  their  absence, 
and  the  fact  that  each  species  of  animals  has  only  a  limited 
number  of  interests  that  dominate  his  activity,  make  it  im- 
possible for  them  to  form  many  free  ideas  and  utterly 
impossible  to  form  any  that  are  so  completely  free  as  are 
those  formed  by  man. 

The  possibility  of  forming  free  ideas  and  of  combining 
movements  without  previous  experience  in  their  combina- 
tion, which  is  involved  in  imitative  acts,  opens  to  man  modes 
of  learning  utterly  impossible  to  animals.  He  can  learn 
not  only  by  his  own  experiences  but  by  the  experiences  of 
others.  He  can  acquire  this  knowledge  not  only  by  imi- 
tating combinations  of  movement,  which  he  would  other- 
wise hit  upon  only  by  accident,  but  he  can  also  profit  by 
the  experience  of  others,  because,  through  the  association 


BEHAVIOR   OF    INDIVIDUALS  139 

of  free  ideas  with  words,  he  can  have  those  ideas  aroused  in 
his  mind  and  combined  in  a  way  corresponding  to  the  ex- 
periences of  other  persons.  This  latter  mode  of  learning 
is  utterly  unattainable  by  animals.  They  may  have  famil- 
iar experiences  recalled  by  words,  but  they  cannot  possibly 
learn  new  things  by  means  of  words.  The  possession  of 
free  ideas  also  makes  it  possible  to  form  trial  ideas  instead 
of  making  actual  trial  movements ;  hence  the  much  greater 
possibilities  of  rapid  learning  by  man. 

REFERENCES 

*Allen,  a.     Some  Experimental  Conclusions  on  Practice  and  Habit, 

Jr.  Ped.,  Vol.  XIX,  pp.  237-254. 
Andrews,  B.  B.     Habit,  Am.  Jr.  Psych.,  Vol.  XIV,  pp.  121-149. 
♦Angell.     Psychology,  Chapter  III. 
♦Arnold,  Felix.     The  Initial  Tendency  in  Ideal  Revival,  Am.  Jr. 

Psych.,  Vol.  XVIII,  pp.  239-252. 
Bair,  J.  H.     The  Acquirement  of  Voluntary  Control,  Psych.  Rev., 

Vol.  VIII,  pp.  474-510. 
Bentley,  I.  M.     The  Memory  Image  and  Its  Qualitative  Fidelity, 

Am.  Jr.  Psych.,  Vol.  XI,  pp.  1-48. 
*Cole,  L.  W.     Concerning  the  Intelligence  of  Raccoons,  Jr.  Comp. 

Neu.  &=  Psych.,  Vol.  XVII,  pp.  211-261. 
*Dexter.     Survival  of  the  Fittest  in  Motor  Training,  Ed.  Rev.,  Vol. 

XXIII,  pp.  81-91. 
*  James.     Psychology,  Chapter  X. 
Jennings,  H.  S.     Progress  in  the  Study  of  the  Behavior  of  the  Lower 

Organisms  during  the  Past  Year,  Psych.  Bui.,  June,  1908,   pp. 

179-190. 
JuDD.     Studies  in  Genetic  Psychology,  Jr.  Ped.,  Vol.  XIII,  pp.  295- 

304- 

* Psychology,  Chapter  VIII. 

*KiRKPATRiCK.     Development  of  Voluntary  Movement,  Psych.  Rev., 

Vol.  XIII,  pp.  275-281. 


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LiNDLEY.     Psychology  of  Puzzles,   Am.  Jr.  Psych.,  Vol.  VIII,  pp. 

431-493- 
Mills,  \V.     Nature  and  Development  of  Animal  Intelligence. 
♦Morgan.     Habit  and  Instinct. 

Comparative  Psychology,  Chapter  XVI. 

Scott.     Se.x  and  Art,  Am.  Jr.  Psych.,  Vol.  VII,  pp.  153-226. 
Spence.     Development  of  Voluntary  Motion,  Pop.  Sci.  Mo.,  Vol. 

XIII,  p.  444. 
Swift  and  Schl^yler.     The  Learning  Process,  Psych.  Bui.,  Oct.  15, 

1907. 
*SwiFT,  E.  J.     Studies  in  the  Psychology  and  Physiology  of  Learning, 

Am.  Jr.  Psych.,  Vol.  XIV,  pp.  201-251. 
*Thorndike,  E.  L.     Animal  Intelligence. 

* Elements  of  Psychology,  Chapter  XIII. 

Function  of  Visual  Images,  Jr.  Phil.  Psych.  S^.Sd.  Meth.,  Vol. 

IV,  pp.  324-327- 
Mental    Antecedents    of    Voluntary    Movements,    Jr.    Phil. 

Psych,  df  Sci.  Meth.,  Vol.  IV,  pp.  40-42. 
*Triplett,  N.     The  Educability  of  the  Perch,  Am.  Jr.  Pysch.,  Vol. 

XII,  p.  354- 
*W.ASHBURN.     The  Animal  Mind,  Chapter  X,  XL 
Washburx,  M.  F.,  and  Bentley,  I.  M.     The  Establishment  of  an 

Association  involving  Color  Discrimination  in  the  Creek  Chub, 

Jr.  Comp.  Neu.  &=  Psych.,  Vol.  XVI,  p.  113. 
*Watson,  John.     Imitation  in  Monkeys,  Psych.  Bui.,  June,  1908, 

pp.  169-178. 
*Yerkes.  The  Dancing  Mouse,  Chapters  XII,  XIII,  XIV,  XV,  XVL 
The  Formation  of  Habits  in  the  Turtle,  Pop.  Sci.  Mo.,  Vol. 

LVIII,  p.  519. 
Habit  Formation  in  the  Crayfish,  Harvard  Studies,  Vol.  I. 


CHAPTER   VI 

STRUCTURES    CONCERNED    IN   COMPLEX    BEHAVIOR 
AND    IN   IDEATION 

THE    NERVOUS   APPARATUS    OF    VERTEBRATES 

The  following  abstract  of  the  results  of  Loeser's  experi- 
ments upon  frogs,  which  correspond  closely  with  what  has 
been  found  by  other  investigators,  will  serve  as  an  indica- 
tion of  the  portions  of  the  nervous  apparatus  concerned 
in  the  various  forms  of  behavior  in  vertebrates. 

If  the  cerebrum  is  removed  on  one  side,  there  is  muscular 
weakness  on  the  other  side  of  the  body  that  lasts  for  several 
days,  while  removal  of  both  sides  of  the  cerebrum  produces 
weakness  on  both  sides  that  is  also  only  temporary.  No 
other  marked  change  is  observed  from  the  removal  of  the 
cortex  of  the  cerebrum  only. 

When  the  optic  thalami  (which  are  comparatively  large 
in  the  frog  and  perhaps  correspond  in  function  as  much  to 
the  cerebral  cortex  of  man  as  to  the  thalami,  which  in 
man  are  located  inside  the  cerebrum)  are  removed,  there 
is  considerable  loss  of  sight  and  of  the  sense  of  touch.  If 
only  one  of  the  thalami  is  removed,  the  decreased  sen- 
sitiveness is  on  the  opposite  side  only  and  is  not  so  great 
as  when  both  are  removed.  The  animal  no  longer  re- 
sponds to  suggestive  stimuli  in  the  form  of  flies,  as  does 
a  normal  frog,  and  he  shows  little  improvement  in  sen- 
sitiveness though  allowed  to  live  for  a  long  while  after 

the  operation. 

141 


142  GENETIC   PSYCHOLOGY 

If,  in  addition  to  the  thalami,  the  optic  lobes  are  removed, 
what  is  known  as  "  forced  movements"  are  common.  The 
limbs  assume  unusual  positions  and  the  animal  when  stimu- 
lated may  respond  with  such  vigorous,  uncontrolled  jumps 
as  to  injure  himself.  The  removal  of  both  lobes  produces 
more  marked  results  than  the  removal  of  one,  but  with  no 
special  difference  in  character,  and  in  either  case  there  is 
little  or  no  recovery.  If  only  the  posterior  portions  of  the 
optic  lobes  are  removed,  other  parts  being  uninjured,  there 
is  no  loss  of  sight,  and  there  is  recovery  after  several  weeks 
from  the  condition  in  which  forced  movements  are  promi- 
nent. 

The  removal  of  the  cerebellum  results  chiefly  in  weakness 
of  movement.  In  higher  animals  injury  to  one  side  of  the 
cerebellum  may  produce  circular  movements. 

The  removal  of  all  of  the  brain  above  the  medulla  leaves 
the  animal,  after  recovering  from  the  operation,  with  the 
power  to  croak,  to  turn  over,  and  to  swallow  in  response  to 
direct  stimulation,  and  also  to  move  into  a  more  favorable 
position  when  the  object  upon  which  the  animal  is  resting 
is  tipped.  The  physiological  processes  of  circulation  and 
respiration  are  carried  on  as  in  the  normal  frog.  He  does 
not  respond  to  suggestive  stimuli,  and  makes  few  or  no 
movements  except  when  externally  stimulated,  and  then 
his  movements  are  very  definite,  so  that  one  who  is  familiar 
with  an  animal  in  this  condition  can  predict  with  almost 
absolute  certainty  just  what  he  will  do. 

When  the  whole  brain  of  a  frog  was  removed,  including 
the  medulla,  leaving  nothing  but  the  spinal  cord  and  the 
sense  and  motor  apparatus  connected  with  it,  the  physio- 
logical process  of  respiration  and  heart  beat  ceased,  though 


STRUCTURES  COx\CERNED  IN  COMPLEX    BEHAVIOR     143 

life  was  maintained  for  five  hours.  In  this  condition  the 
animal  showed  no  evidence  of  sight,  did  not  turn  over 
when  placed  on  its  back,  did  not  move  when  the  surface 
upon  which  it  was  resting  was  tipped,  and  the  croaking  and 
swallowing  reflexes  could  not  be  called  forth.  Tactile 
stimuli,  on  the  other  hand,  were  responded  to  by  move- 
ments of  the  limbs  more  quickly  and  accurately  than  in  the 
case  of  a  normal  animal. 

When  a  portion  of  the  cord  next  the  brain  was  removed 
so  as  to  affect  the  centers  concerned  in  the  movements  of  the 
fore  limbs,  incoordination  of  movement  appeared  and  the 
animal  could  no  longer  move  its  body  as  a  whole  success- 
fully. Considerably  more  of  the  cord  could  be  removed, 
however,  without  interfering  seriously  with  the  movements 
of  the  hind  legs  when  the  animal  was  suspended  in  such  a 
position  that  movements  could  be  freely  made. 

These  results  correspond  in  a  general  way  with  the  re- 
sults of  experiments  on  higher  animals.  In  the  case  of 
higher  animals,  the  results  of  removal  of  portions  of  the 
nervous  system  are  likely  to  be  more  profound  and  perma- 
nent, and  the  animal  is  more  likely  to  die  from  the  injuries. 
Goltz,  however,  who  succeeded  in  removing  practically  the 
whole  of  the  cerebrum  of  a  dog  without  destroying  its  life, 
found  that  the  animal  reacted  like  normal  animals  to  direct 
sense  stimuli  but  showed  no  evidence  of  memory,  intelli- 
gence, pleasure,  or  envy,  and  that  its  responses  to  stim- 
uli were  immediate  rather  than  deliberate. 

From  these  experiments  we  may  conclude  that  the 
physiological  processes  are  chiefly  under  the  control  of  the 
medulla  in  connection  with  the  sympathetic  nervous  sys- 
tem.    The  reflex  movement  of  swallowing,  so  closely  con- 


144  GENETIC   PSYCHOLOGY 

nccted  with  the  physiological  processes,  and  some  other 
complex  reflexes,  arc  also  under  the  control  of  the  medulla. 

The  simpler  reflex  movements  in  response  to  direct 
tactile  stimulation  are  chiefly  under  the  control  of  the  spinal 
cord,  while  the  ganglia  between  the  medulla  and  the  cortex, 
the  optic  thalami,  the  corpora  striata,  and  the  corpora  quad- 
rigemina  (sometimes  called  collectively  the  "basal  ganglia") 
are  concerned  in  the  more  complex  reflex  and  instinctive 
movements  of  the  whole  body  in  response  to  direct  sensory 
stimulation. 

The  nervous  energy  concerned  in  stimulating  the  motor 
centers  to  action  seems  to  be  stored  up  in  part  in  the  cere- 
bellum and  probably  also  in  the  cortex  of  the  cerebrum. 
These  organs  therefore  make  it  possible  for  movements  to 
be  executed  with  vigor,  and  they  doubtless  are  concerned 
in  the  coordination  of  movements,  since  they  determine 
the  amount  of  energy  sent  to  various  centers  of  move- 
ment. An  injury  to  one  side  of  the  cerebellum  therefore 
naturally  interferes  with  balance  and  coordination  of 
movement. 

The  more  conscious  processes  involved  in  responding  to 
suggestive  stimuli  and  in  carrying  on  the  higher  mental 
processes  are  made  possible  by  means  of  the  wonderful 
complex  structure  of  the  cerebral  cortex,  whose  most 
marked  characteristic  is  its  capacity  for  being  modified 
by  experience.  It  thus  becomes  a  great  storehouse  of  past 
experiences  and  an  organ  for  bringing  present  and  past 
stimuli  into  relation  with  each  other  so  as  to  direct  activity 
toward  definite  ends.  The  frontal  lobes  of  this  organ  seem 
to  be  especially  concerned  in  the  coordinating  activity  of 
attention  by  means  of  which  mental  and  motor  processes 


STRUCTURES  CONCERNED  IN  COMPLEX   BEHAVIOR     145 

are  unified  and  directed  toward  a  definite  end.  In  the  low- 
est vertebrates,  which  have  scarcely  anything  that  can  be 
called  a  cerebrum,  there  is  very  little  reaction  to  suggestive 
stimuli  and  very  little  capacity  for  learning  by  experience. 

The  functioning  of  the  frontal  lobes  in  learning  is  clearly 
indicated  by  the  experiments  of  Franz.  He  trained  mon- 
keys to  perform  tricks,  then  removed  the  frontal  lobes. 
There  was  no  indication  of  paralysis  or  of  loss  of  sensa- 
tion, but  the  animals  did  not  seem  to  perceive  the  mean- 
ing of  objects  and  signals  involved  in  the  tricks  recently 
learned  and  for  that  reason  apparently  could  not  perform 
them.  Instincts  and  well-established  habits  on  the  con- 
trary were  unaffected.  This  indicated  that  the  frontal 
lobes,  which  are  concerned  in  the  unifying  act  of  attention, 
are  necessary  to  the  learning  of  complex  acts  and  to  the 
successful  execution  of  them  until  the  apparatus  more 
immediately  concerned  in  their  execution  is  so  well  devel- 
oped that  it  may  function  successfully  without  the  direct- 
ing activity  of  the  frontal  lobes. 

Similar  conclusions  may  be  drawn  from  the  noted  case 
of  a  workman  who  had  a  large  portion  of  the  front  of 
one  half  of  the  brain  destroyed  by  a  crowbar  which  passed 
through  the  side  of  his  head.  It  has  sometimes  been  stated 
that  he  showed  little  evidence  of  the  loss  of  function  after 
the  wound  had  healed.  As  a  matter  of  fact,  a  careful 
study  of  the  description  of  his  actions  and  his  subsequent 
life  shows  that  his  dis[)osition  and  intellectual  ability  were 
changed  in  a  marked  way,  although  his  habitual  acts  were 
performed  about  as  well  as  ever.  He  was  more  moody, 
impulsive,  and  less  controlled  in  his  actions,  and  he  was 
unable  to  concentrate  his  mind  in  the  planning  of  new 


146  GENETIC   PSYCHOLOGY 

work.     In  consequence  of  these  deficiencies  he  was  obliged 
to  give  up  his  position  as  a  foreman. 

rttFFERENCES    BETWEEN    THE    NERVOUS    SYSTEM    OF    MAN 
AND    OF    OTHER    ANIMALS 

In  order  to  explain  the  wonderfully  complex  activities 
possible  to  human  beings  we  must  notice  some  of  the  promi- 
nent differences  between  the  brain  of  man  and  of  the  lower 
animals.  The  spinal  cord  of  man  is  very  much  the  same 
as  in  other  of  the  higher  vertebrates,  though  it  is  perhaps 
more  highly  specialized  in  man  into  an  organ  for  connect- 
ing the  surface  of  the  body  with  certain  portions  of  the 
brain,  while  in  animals  the  cord  is  not  concerned  so  much 
in  making  connections  with  the  brain  as  it  is  in  responding 
itself  to  tactile  stimulations.  The  total  size  of  the  cord  is 
small  in  man  as  compared  with  other  vertebrates,  espe- 
cially the  lower  ones,  and  his  brain  is  relatively  very  large. 

The  brain  of  man  is  absolutely  larger  than  the  brain  of 
any  but  the  largest  vertebrate,  and  relatively  larger,  in 
proportion  to  the  size  of  the  body,  than  in  any  but  the 
smallest  vertebrate,  while  in  comparison  to  the  rest  of  the 
nervous  system  it  is  relatively  larger  than  that  of  any 
other  animal. 

As  we  have  previously  seen,  man  is  endowed  with  highly 
specialized  sense  organs  and  with  a  motor  apparatus  that 
admits  of  great  variety  and  accuracy  of  movement,  this 
variety  and  accuracy  of  movement  being  made  possible 
by  the  possession  of  a  few  motor  organs  whose  movements 
can  be  combined  in  an  infinite  variety  of  ways.  A  motor 
apparatus  of  this  type  would  not  be  effective  if  it  were  not 


STRUCTURES  CONCERNED  IN  COMPLEX  BEHAVIOR    147 

connected  with  a  nervous  apparatus  of  sufTicicnt  size  to 
effect  the  proper  connections  and  adjustments  involved 
in  the  various  combinations  that  are  required,  just  as 
many  telephones  in  a  system  demand  a  large  switchboard. 
This  is  one  reason  why  the  brain  of  man  needs  to  be  much 
larger  than  that  of  any  other  animal. 

Man  is  still  further  distinguished  by  the  size  of  his 
cerebrum  in  proportion  to  the  rest  of  the  brain,  and  still 
further  by  the  large  size  of  the  frontal  and  parietal  lobes. 
These  facts  are  doubtless  correlated  with  the  fact  that  man 
has  many  instincts  not  possessed  by  animals  and  is  cap- 
able of  many  forms  of  mental  activity  impossible  to  them. 

In  comparing  the  surface  of  the  cerebrum  of  man  with 
that  of  the  dog  or  the  monkey  there  is  a  general  corre- 
spondence, though  the  frontal  and  parietal  regions  are  in 
man  much  larger  and  contain  an  immensely  greater  number 
of  connecting  nerve  elements. 

In  a  young  child  only  a  comparatively  small  portion 
of  the  surface  of  the  cerebrum  is  connected  with  other 
parts  of  the  nervous  system  by  meduUated  nerve  fibers. 
The  sense  centers  having  medullated  nerve  connections 
are  connected  not  with  each  other  but  with  the  basal 
ganglia  and  the  spinal  cord.  Medullation  of  nerve  fibers 
probably  corresponds  in  a  general  way  to  the  insulating 
cover  on  electric  wires,  preventing  impulses  from  spreading 
to  other  nerve  elements.  It  probably  indicates  not  merely 
that  impulses  may  pass  to  and  from  centers  connected  by 
such  fibers,  but  that  impulses  passing  over  these  fibers 
must  pursue  a  definite  course.  The  medullation  of  fibers 
is  therefore  probably  correlated  in  part  at  least  with  learn- 
ing and  habit  formation. 


148  GENETIC   PSYCHOLOGY 

As  the  infant  grows  older  and  has  experiences  by  means 
of  which  he  learns  to  make  all  sorts  of  combinations  of 
motor  apparatus  under  various  circumstances  of  stimu- 
lation, the  nerve  fibers  having  medullary  sheaths  increase 
in  number.  Those  connecting  the  various  sense  centers 
in  the  cortex  with  each  other  soon  acquire  their  medullary 
sheaths.  In  a  child  the  spaces  between  the  sense  centers, 
sometimes  called  "association"  centers,  are  much  greater 
than  in  animals.  This  probably  corresponds  to  the  fact 
that  young  animals  are  capable  of  many  instinctive  move- 
ments, while  the  child  is  capable  of  very  few,  but  has  a 
much  greater  capacity  for  acquiring  new  combinations  of 
movement. 

The  fact  that  large  portions  of  the  cortex  in  the  child  are 
unmedullated,  and  that  the  number  of  medullated  fibers 
continues  to  increase  in  the  cortex  of  man  long  after  he  is 
physically  mature  and  has  practically  ceased  to  learn  new 
combinations  of  movement,  indicates  that  there  are  other 
functions  performed  by  the  'cortex  of  man  than  those  of 
combining  movements.  Some  of  these  portions  of  the 
cortex  that  at  birth  are  unmedullated  doubtless  constitute 
the  apparatus  by  means  of  which  man  is  able  to  store  up 
the  results  of  past  experience  in  the  form  of  free  images 
and  ideas. 

It  has  long  been  known  that  sensation  and  movement 
may  be  lost  through  injury  to  the  spinal  cord  without  the 
higher  intellectual  powers  being  affected.  It  is  also  not 
unusual  when  the  brain  is  injured  or  diseased  for  the  mental 
powers  to  be  seriously  affected  without  any  disturbance  of 
sensation  and  movement. 

More  definite  localization  of  mental  functions  was  first 


STRUCTURES  CONCERNED  IN  COMPLEX   BEHAVIOR     149 

clearly  established  in  the  case  of  portions  of  the  brain 
concerned  in  the  use  of  symbols.  It  was  found  that  in- 
juries to  the  left  hemisphere  in  the  temporal  region  usually 
resulted  in  language  disturbance  of  some  kind,  designated 
by  the  general  term  "  aphasia."  The  particular  portion  of 
the  brain  concerned  in  the  use  of  symbols,  especially  words, 
was  discovered  doubtless,  not  because  the  functions  in- 
volved in  language  are  more  defmitely  localized  than  are 
other  functions,  but  because  any  deficiency  in  language 
could  more  easily  be  detected  and  its  exact  nature  more 
accurately  determined  than  a  deficiency  in  any  other  men- 
tal power.  It  is  for  this  same  reason  that  further  facts  as 
to  the  exact  portion  of  the  cortex  concerned  in  different 
forms  of  language  functioning  have  been  determined  with 
a  good  deal  of  accuracy.  Injuries  to  other  portions  of  the 
brain  may  not  produce  changes  in  mental  characteristics 
that  a  stranger  would  detect,  while  friends  would  be  able 
only  to  say  that  the  indix'idual  is  "queer,"  without  discern- 
ing the  exact  deficiency. 

The  deficiency  in  language  may  consist  in  inability  to 
understand  spoken  words,  although  there  is  no  deafness  to 
sounds;  or  inability  to  understand  the  meaning  of  visual 
words,  although  sight  is  not  affected ;  or  inability  to  speak 
words,  although  there  is  no  paralysis  and  words  may  be 
understood ;  or  inability  to  write,  although  the  arm  is  not 
paralyzed  and  words  are  recognized  and  understood  when 
seen.  These  various  deficiencies,  which  have  received 
technical  names,  may  be  combined  in  all  sorts  of  ways,  but 
one  may  appear  almost  wholly  alone,  and  perhaps  exist 
only  for  certain  classes  of  words,  in  persons  who  show  no 
sensory  or  motor  deficiency  and  who  can  form  images  of 


150  GENETIC    PSYCHOLOGY 

things  and  reason  as  well  as  they  ever  could.  It  seems 
quite  certain,  therefore,  that  there  is  a  certain  portion  of 
the  brain  especially  concerned  in  the  use  of  symbols,  al- 
though it  is  complex  in  character  and  closely  associated 
with  apparatus  concerned  in  other  mental  functions. 

Detailed  evidence  as  to  the  existence  of  specific  apparatus 
concerned  in  the  various  other  forms  of  mental  activity  is 
not  so  easily  obtained  and  not  so  clearly  established  as  in 
the  case  of  the  language  apparatus.  There  is  sufficient, 
evidence,  however,  to  justify  the  claim  that  the  apparatus 
concerned  in  imaging  things  is  not  wholly  the  same  as  that 
concerned  in  sensing  them.  Experiment  shows  that,  when 
coming  under  the  influence  of  chloroform,  the  power  to 
image  and  to  think  remains  after  all  sensation  is  lost. 
This  indicates  that  the  centers  concerned  in  these  pro- 
cesses are  not  the  same  as  those  concerned  in  sensations. 
The  phenomena  of  dreaming  supports  this  view. 

A  most  striking  illustration  of  the  fact  that  the  apparatus 
concerned  in  imaging  is  distinct  from  that  concerned  in 
sensation  and  in  thought,  is  furnished  by  the  instance  of  a 
man  who  was  an  exceptionally  good  visualizer,  so  good  that 
he  could  image  a  business  letter  as  a  whole  and  read  it 
just  as  if  it  were  before  his  eyes.  After  a  period  of  mental 
strain  he  found  himself  utterly  unable  to  form  visual 
images.  He  could  no  longer  use  such  images  in  memory 
as  formerly,  and  buildings  and  persons  that  he  had  long 
known  also  seemed  strange  to  him.  His  reason  was  un- 
affected and  he  continued  to  carry  on  his  business  suc- 
cessfully. In  order  to  do  so  he  practiced  using  auditory 
images,  remembering  in  this  way  what  he  had  formerly 
remembered  in  the  form  of  visual  images.     This  is  only 


STRUCTURES  CONCERNED  IN  COMPLEX   BEHAVIOR     151 

one  of  the  most  striking  of  many  cases,  indicating  that  the 
image  centers  are,  at  least  in  part,  distinct  from  the  sen- 
sory centers  and  the  conceptual  centers.  Pathological  cases 
and  hypnotic  experiments  furnish  other  instances  which, 
as  we  shall  see,  are  supported  by  psychological  analysis. 

The  nervous  system  of  man  can  best  be  conceived  as 
being  very  much  like  that  of  dogs,  monkeys,  and  other 
animals,  but  with  considerable  portions  specialized  for  the 
performance  of  more  complex  operations.  Those  centers 
which  are  slightly  if  at  all  represented  in  the  brains  of 
the  lower  animals  are  first,  centers  concerned  in  forming 
images  of  things;  second,  those  concerned  in  the  produc- 
tion of  word  or  symbol  images;  and  third,  those  concerned 
in  the  formation  of  concepts  and  in  the  processes  of 
abstract  thought. 

The  imaging  centers  are  excited  to  action  primarily 
by  external  stimulations  that  pass  through  the  centers 
concerned  in  sensation.  These  image  centers,  when 
developed  by  experience,  may  send  impulses  to  each 
other  without  the  centers  concerned  in  sensation  and 
movement  being  concerned  in  the  activity  to  any  consider- 
able extent.  They  may  also  be  excited  to  activity  by  im- 
pulses coming  from  the  centers  concerned  in  the  produc- 
tion of  word  images  and  also  by  images  coming  from  the 
conceptual  centers. 

The  symbol  or  word-imaging  centers  are  excited  pri- 
marily by  external  stimulation  passing  through  the  sen- 
sory centers,  just  as  are  the  centers  for  imaging  things ;  but 
when  fully  developed  may  be  excited  from  other  word 
centers  and  by  impulses  coming  from  the  conceptual 
centers. 


152  GENETIC   PSYCHOLOGY 

The  conceptual  centers  are  excited  primarily  by  impulses 
from  the  image  centers  and  from  the  word  centers.  The 
same  centers  are  concerned  to  a  considerable  extent  in 
attention.  When  developed,  one  conceptual  center  may 
arouse  another  to  actix'ity  either  with  or  without  the  exci- 
tation of  the  image  centers. 

What  is  practically  the  same  external  reaction,  for 
example,  the  drawing  away  of  the  hand,  may  be  directed 
wholly  by  the  sensory  motor  apparatus  excited  by  an  ex- 
ternal stimulus,  or  may  be  produced  without  an  external 
stimulation  by  an  impulse  coming  from  either  of  the  three 
centers  already  named.  It  is  because  of  this  fact  that  a 
creature  with  such  centers  is  to  a  considerable  extent  inde- 
pendent of  his  environment,  being  able  to  act  in  accordance 
with  images  of  past  experience  instead  of  in  response  to 
present  stimulations  only. 

Some  specialization  in  the  brain  structure  of  the  higher 
animals  may  exist,  corresponding  to  one  or  more  of  those 
centers  named  above  as  existing  in  the  brain  of  man,  but 
the  specialization  has  not  proceeded  far  enough  to  admit 
of  very  much  independent  activity  of  those  centers.  It  is 
not  possible  therefore  for  animals  to  carry  on  to  any  con- 
siderable extent  the  function  of  imaging  independently  of 
external  stimulation  and  of  external  movement,  because  the 
apparatus  for  independent  action  of  such  centers  is  not 
sufficiently  developed. 

GENERAL    VIEW    OF    BRAIN    FUNCTIONING 

In  man  the  various  mechanisms  concerned  in  mental 
processes   can   function   to   a   considerable   extent   inde- 


STRUCTURES  CONCERNED  IN  COMPLEX    BEHAVIOR 


153 


pendenlly,  bul  one  may  readily  start  another  into  action 
and  these  higher  centers  in  the  brain  inllucnce  and  are  in- 
lluenced  by  the  basal  ganglia,  the  spinal  cord,  and  the  sym- 
pathetic nervous  system.  The  relations  between  the  vari- 
ous parts  of  the  nervous  sys- 
tem and  the  possibilities 
of  separate  and  combined 
action  may  be  conceived  as 
being  similar  to  the  rela- 
tion between  boiler,  engine, 
lathes,  drills,  etc.,  of  a  large 
machine  shop,  only  infinitely 
more  complex  and  delicately 
adjusted. 

The  accompanying  dia- 
gram may  help  to  give  a 
general  idea  of  the  various 
apparatus  concerned  in  the 
mental  and  motor  opera- 
tions of  man  and  the  rela- 
tion of  one  part  to  another. 

To     simplify     matters    each      Fig.  15. -Diagram  showing  in  a  general 

type  of  apparatus   is   repre- way  the  relation  between  the  conceptual, 

,11  •       1         .     ,  representative,  and  svTnbol  centers  of  the 

sented  by  a  smgle  circle  or         ,     ,  ,,  ■       ,      ,       , ., 

-'  rt  upper  level,  the  perceptual  centers  of  the 

center.      As  a  matter  of  fact,  midflle  level,  and  the  instinctite,  reflex, 

all  of  these  centers  are  com-^"^P^^'''"'°^"''""*'^''°^"^'^^°^^"^'='""'' 
plex,  and  their  parts,  instead  of  being  located  together,  are 
found  in  different  parts  of  the  brain.  For  example,  the 
sensory  motor  center  includes  all  the  special  senses, 
although  the  auditory  center  is  near  the  middle  of  the 
cerebrum  and  the  visual  center  in  the  back  portion.      On 


154  GENETIC   PSYCHOLOGY 

the  Hughlings  Jackson"  three  level  theory"  the  conceptual, 
symbolic,  and  representative  centers  vi'ould  constitute  the 
upper  level,  the  perceptual  centers  the  second,  and  the 
instinctive,  physiological,  and  reflex  the  third. 

In  considering  the  function  of  the  nervous  system  two 
important  principles  have  until  recently  been  largely  ig- 
nored or  not  given  sufficient  weight  by  physiologists  and 
psychologists.  These  are  (i)  what  has  been  designated 
in  mechanics  as  the  "factor  of  safety"  in  construction 
and  only  recently  recognized  as  applicable  to  the  body,  and 
(2)  the  principle  of  the  "common  path"  made  so  much  of 
in  Sherrington's  great  work  on  the  physiology  of  the  nerv- 
ous system. 

Mechanics  always  recognize  the  factor  of  safety  in  their 
constructions  by  making  a  bridge  or  other  structure  from 
six  to  ten  times  as  strong  as  is  needed  to  bear  the  strain 
to  which  it  is  likely  to  be  subjected.  In  many  machines 
the  same  principle  is  recognized  by  having  several  sets  of 
apparatus  to  do  the  same  work,  so  that  the  machine  will 
be  effective  when  subjected  to  unusual  strain  or  when  some 
portion  of  it  is  broken  or  out  of  order.  In  the  construc- 
tion of  the  body,  nature  has  recognized  this  principle  to 
as  great  if  not  a  greater  extent  than  have  machinists. 
Men  have  lived  for  years  and  done  their  ordinary  work 
with  only  a  part  of  one  lung,  a  portion  of  the  liver,  or  a  part 
of  one  kidney ;  and  it  has  recently  been  demonstrated  that 
even  so  important  an  organ  as  the  stomach  may  be  removed 
and  yet  the  process  of  digestion  be  carried  on  successfully. 
There  is  no  doubt  that  the  nervous  system  is  constructed 
in  such  a  way  that  considerable  portions  of  it  may  be  de- 
stroyed without  permanently  interfering  with  the  functions 


STRUCTURES  CONCERNED  IN  COMPLEX    BEHAVIOR     155 

that  they  have  previously  i)erformed  wholly  or  in  part. 
If  the  visual  center  is  lost,  auditory  images  may  take  the 
place  of  the  visual,  or  the  same  work  may,  under  certain 
circumstances,  be  performed  by  a  conceptual  center  or  by 
the  sensory  motor  apparatus. 

The  principle  of  the  "  common  path"  is  correlated  and  to 
some  extent  contrasted  with  that  of  the  "factor  of  safety." 
If  the  path  concerned  in  the  execution  of  movements  is  in- 
jured, certain  functions,  e.g.  writing,  which  might  otherwise 
have  been  directed  either  by  sensory,  representative,  or  con- 
ceptual centers,  may  be  interfered  with.  Again,  injury  to 
a  sensory  tract  leading  from  the  lower  to  the  higher  centers 
may  interfere  with  the  activity  of  sensory,  conceptual,  and 
representative  centers  in  the  performance  of  certain  kinds 
of  tasks;  e.g.  injury  to  the  optic  nerve  prevents  reading. 
Again,  the  development  of  a  certain  kind  of  motor  ability 
may  increase  in  a  marked  way  the  power  of  conceptual,  rep- 
resentative, and  sensory  centers.  A  striking  instance  of  this 
is  that  of  a  man  who  could  not  talk  and  was  supposed  to  be 
an  imbecile,  unable  to  master  the  simplest  subjects.  After 
an  operation  on  the  tongue  and  some  training  of  the  vocal 
organs,  he  developed  mentally  and  later  became  a  success- 
ful business  man.  Skill  in  drawing  always  increases  the 
fineness  of  sense  discrimination,  clearness  of  representation, 
and  variety  and  defmiteness  of  conception.  In  the  other 
direction  the  development  of  a  clear  concept  may  increase 
the  representative  and  perceptive  power  and  sensitiveness 
in  the  same  line,  as  is  shown  by  the  fact  that  one  who  is 
familiar  with  an  object  sees  it  more  readily. 

Many  machines  are  capable  of  doing  a  great  variety  of 
things  by  means  of  special  attachments;  e.g.  the  sewing 


156  GENETIC   PSYCHOLOGY 

machine,  although  the  machine  as  a  whole  works  in  much 
the  same  way  with  one  attachment  as  with  another.  In  a 
similar  way  we  may  suppose  that  higher  animals  and  man, 
with  the  same  general  type  of  nervous  system,  are  enabled 
to  do  an  increasing  variety  of  things  because  of  some  spe- 
cialization in  motor,  sensory,  or  representative  apparatus. 
The  nervous  system  of  some  of  the  lower  animals  may  be 
compared  to  the  old  hand  printing  press  and  that  of  the 
higher  to  the  modern  Hoe  press.  The  general  character 
of  the  result  is  the  same,  but  with  the  modern  machine  the 
process  is  infinitely  more  com}jlex  and  rapid. 

PHYSIOLOGICAL    BASIS    OF    SPECIAL    MENTAL    PROCESSES 

The  various  mental  processes  described  in  psychology, 
when  considered  from  the  physiological  point  of  view,  must 
be  conceived  as  the  functioning  of  neural  elements  organized 
so  as  to  react  in  certain  relations.  In  the  case  of  reflex  and 
instinctive  processes  these  organizations  of  elements  are 
largely  structural  and  independent  of  experience.  In  the 
case  of  conscious  processes  described  in  psychology  the 
organization  has  been  produced,  in  part  at  least,  by  experi- 
ence, the  relations  of  neural  elements  to  each  other  being 
modified  by  every  experience  of  combined  activity. 

In  perception,  the  physiological  apparatus  involved  is 
much  more  complex  than  that  concerned  in  simple  sensory 
motor  reactions  and  is  to  a  much  greater  extent  the  result  of 
experience.  The  variety  of  specialized  elements  concerned 
in  perceptions  is  as  much  greater  than  of  those  concerned  in 
reflex  movement  as  is  the  nervous  apparatus  of  a  frog  more 
complex  than  that  of  the  hydra.     The  perception  of  any 


STRUCTURES  CONCERNED  IN  COMPLEX    BEHAVIOR      157 

object,  as  for  example  an  apple,  may  involve  correlated 
activity  of  nervous  elements  located  in  visual,  auditory, 
tactile,  olfactory,  and  motor  centers  of  the  brain.  Re- 
peated and  various  experiences  with  such  an  object  cause 
elements  in  all  these  centers  to  become  related  and  or- 
ganized into  a  perceptual  apparatus  all  of  which  is  active 
to  some  extent  whenever  one  of  the  sensory  centers  con- 
cerned is  stimulated.  The  functioning  of  such  an  appara- 
tus is  the  physiological  side  of  the  process  indicated  in 
psychology  by  the  name  perception.  A  definite  object, 
usually  located  spatially,  is  perceived  whenever  this  appa- 
ratus is  excited  to  activity,  whatever  the  sense  by  which  the 
activity  may  be  initiated.  Our  perception  of  a  book  is 
much  the  same  whether  we  see  it,  hear  it  fall,  or  touch  it. 

The  perception  differs  greatly,  however,  according  to  the 
kind  of  interest  we  have  in  the  book  at  the  moment  and 
what  movements  we  are  going  to  make  in  connection  with 
it.  This  means  that  the  functioning  of  the  perceptual 
apparatus  is  influenced  by  other  apparatus  dominating 
and  determining  the  general  character  of  the  activity  of 
the  perceptual  apparatus.  The  percept  of  a  flower  as  an 
object  of  beauty  is  entirely  different  from  the  percept  of 
the  same  flower  as  an  article  of  merchandise,  as  a  scien- 
tific specimen,  or  as  a  cure  for  a  certain  disease.  It  is 
probably  not  too  much  to  say  that  the  perceptual  reaction 
of  a  man  to  a  single  object  may  in  a  few  minutes  involve 
as  much  variety  in  physiological  and  mental  activity  as  is 
shown  in  the  reactions  of  a  frog  to  all  phases  of  his  envi- 
ronment during  his  whole  life. 

A  percept  is  to  be  thought  of,  not  as  a  mere  comljination 
of  sensations,  but  as  the  result  of  the  functioning  of  a 


158  GENETIC   PSYCHOLOGY 

highly  organized  perceptual  apparatus  usually  dominated 
by  higher  centers  and  discharging  into  definite  motor 
channels.  Sensations  involve  the  activity  of  a  simple 
apparatus  long  used  by  the  species,  while  perception  in- 
volves the  activity  of  a  much  more  complex  apparatus 
organized  by  repeated  experiences  of  the  individual. 
It  probably  always  involves  the  activity  of  at  least  one  sen- 
sory center  other  than  that  directly  stimulated,  along  with 
the  activity  of  centers  determining  attention,  and  motor 
centers,  and  in  man,  imaging  and  conceptual  centers  as 
well. 

If  the  perceptual  apparatus  is  excited  by  a  stimulus 
affecting  a  sensory  center,  one  may  seem  to  have  a  percept 
of  an  object  that  is  not  present.  Hallucinations  are  not 
produced,  as  is  sometimes  thought,  merely  by  excessive 
activity  of  the  imaging  centers,  although  the  activity  of 
such  centers  may  help  to  determine  the  particular  character 
of  the  hallucination.  A  real  object  seems  to  be  perceived 
instead  of  being  merely  imaged  because  in  some  w^ay, 
either  because  of  irritation  of  nerves  leading  to  sensory 
centers,  or  because  of  an  external  stimulus  of  a  general 
character,  the  perceptual  apparatus  is  excited  from  the 
periphery.  Only  when  thus  excited  does  one  have  the 
feeling  of  the  reality  of  the  perception  and  fail  to  distin- 
guish it  from  an  image. 

Mental  images  are  the  result  of  impulses  that  do  not  come 
directly  from  the  periphery  as  in  perceptions.  They  in- 
volve the  functioning  of  apparatus  that  is  at  least  partially 
different  from  that  involved  in  perception.  In  so  far  as  the 
centers  concerned  are  the  same,  they  are  made  active  in 
perception  by  impulses  coming  from  a  sensory  center, 


STRUCTURES  CONCERNED  IN  COMPLEX   BEHAVIOR     159 

while  in  imaging  they  may  be  made  active  by  impulses 
coming  from  some  other  direction.  The  power  to  image 
may  remain  after  the  power  to  make  the  corresponding 
perception  has  been  lost,  and  there  may  be  power  to  per- 
ceive or  recognize  objects  that  cannot  be  imaged  when  they 
are  not  present.  This  does  not  necessarily  mean,  however, 
that  the  apparatus  concerned  in  the  two  processes  is  wholly 
different,  but  only  that  it  is  partially  different  and  excited 
to  activity  in  a  different  way. 

A  percept,  being  produced  by  an  object,  is  necessarily 
perceived  in  space  and  in  relation  to  what  surrounds  it. 
A  free  image,  on  the  other  hand,  is  not  necessarily  connected 
in  any  way  with  surrounding  objects,  but  may  be  associated 
in  any  desired  way  with  other  images  which  are  also  not 
connected  with  any  object  at  the  moment  stimulating 
the  senses.  Free  images  are  under  subjective  control, 
and  the  apparatus  concerned  is  usually  excited  internally, 
while  percepts  are  objectively  initiated  and  the  apparatus 
concerned  is  made  active  by  some  object  in  the  immediate 
surroundings. 

In  purposeful  perception,  however,  the  activity  of  the 
sense  centers  concerned  is  doubtless  increased  and  modified 
by  impulses  from  within.  In  perception,  impulses  usually 
discharge  to  some  extent  into  motor  centers,  while  in 
imaging,  the  discharge  is  directly  into  other  imaging  centers 
or  into  conceptual  centers,  and  if  there  is  any  discharge 
at  all  into  motor  centers,  it  is  indirect  rather  than  direct. 

The  imaging  apparatus  is  first  developed  by  impulses 
from  sensory  centers,  but  free  images  are  not  formed  till 
the  imaging  apparatus  can  be  excited  from  several  direc- 
tions and  can  have  its  connection  with  other  apparatus 


l6o  GENETIC   PSYCHOLOGY 

readily  shifted  so  as  to  effect  a  variety  of  combinations. 
This  is  a  marked  characteristic  of  the  imaging  apparatus, 
that  its  units  may  be  united  or  disconnected  in  almost 
any  desired  way  with  great  facility,  just  as  we  may  sep- 
arate and  combine  letters.  While  the  perceptive  apparatus 
is  comparatively  stable  in  its  organization,  always  present- 
ing the  same  combination  of  qualities,  yet  one  may  be 
emphasized  more  than  another  according  to  the  kind  and 
intensity  of  the  external  stimuli  and  the  kind  of  stimulus 
coming  from  the  higher  centers  determining  the  purpose 
of  the  activity. 

Where  other  sense  centers  than  the  one  stimulated  are 
excited,  as  is  the  case  in  nearly  all  perception,  the  resulting 
mental  states  are  more  like  sensations  than  genuine  free 
images ;  e.g.  we  seem  to  actually  feel  the  smoothness,  weight, 
and  coldness  of  a  piece  of  ice  perceived  visually.  The 
term  "mediated"  or  "secondary"  sensations  might  well 
be  applied  to  them.  They  certainly  are  not  free  images,  for 
they  are  the  result  of  co-functioning  of  sense  centers,  one 
of  which  is  directly  stimulated,  while  free  images  are  the 
result  of  separate  functioning  of  centers  either  partially 
or  wholly  different  from  those  concerned  in  sensations. 

Memory  images  differ  from  free  images  in  that  not  only 
does  an  image  unit  occur  again  but  it  occurs  in  the  same 
combination  with  other  units  as  at  some  previous  time. 
If  under  a  given  set  of  circumstances  a  combination  of 
image  units  is  incomplete  or  different  in  arrangement  from 
what  it  was  originally,  the  memory  is  defective.  In  im- 
agination, on  the  other  hand,  change  in  the  way  in  which 
image  units  are  combined  is  an  essential  characteristic. 
On  the  physiological  side  memory  involves  the  making 


STRUCTURES  CONCERNED  IN  COMPLEX   BEHAVIOR     i6i 

of  the  adjustments  or  series  of  adjustments  that  have  been 
made  one  or  more  times  before,  and  on  the  psychical  side, 
the  consciousness  that  the  adjustment  has  been  made 
previously. 

Concepts  are  the  result  of  the  functionina;  of  apparatus 
further  removed  from  direct  stimulation  of  objects  than 
are  the  imaging  centers.  Conceptual  centers  arc  aroused 
to  activity  by  impulses  from  the  image  centers  which,  as  we 
have  seen,  are  primarily  made  active  by  impulses  from  the 
sensory  centers.  When  fully  developed,  the  conceptual 
centers  are  capable  of  being  excited  by  imj)ulses  from  the 
symbol  centers  and  by  impulses  from  other  conceptual 
centers.  Conceptual  centers  are  so  specialized  that  im- 
pulses from  the  perceptual  apparatus  are  more  completely 
analyzed  than  in  the  image  centers,  and  it  is  possible  to 
have  ideas  of  the  qualities  of  objects  totally  unrelated  to 
the  objects  themselves.  This  is  quite  beyond  the  powers 
of  the  perceptual  and  imaging  centers,  which  are  concerned 
to  a  greater  or  less  extent  with  objects  as  wholes  or  with 
qualities  of  objects  instead  of  qualities  unrelated  to  objects. 
This  greater  specialization  of  activity  is  correlated  w^ith 
an  increased  capacity  for  making  all  sorts  of  combinations 
of  these  qualities.  On  the  physiological  side  this  doubt- 
less means  much  greater  specialization  of  fine  neural 
elements,  and  at  the  same  time  much  more  complex  and 
extensive  combinations  of  neural  elements,  that  may  be 
made  and  changed  with  the  greatest  facility. 

Combinations  and  changes  of  adjustment  of  neural 
elements  are  involved  in  acts  of  attention,  association, 
and  thinking,  and  such  acts  determine  the  general  direction 
of  the  activity  of  the  imaging  and  perceptual  apparatus. 


l62  GENETIC   PSYCHOLOGY 

Injury  to  the  attentive-conceptual  centers  may  affect 
the  action  of  the  lower  centers  because  the  adjusting  and 
organizing  power  is  affected.  Simple  sensory  motor 
processes  are  usually  less  affected,  and  the  same  is  true 
of  the  perception  of  familiar  objects,  while  new  percep- 
tions and  all  combinations  of  image  and  conceptual  units 
are  impossible  except  in  the  case  of  some  that  are  very 
well  established  by  habitual  activities. 

Conceptual  activity  doubtless  involves  the  activity  of  an 
apparatus  as  complex  and  highly  differentiated  in  com- 
parison with  the  perceptual  apparatus  as  the  perceptual 
is,  compared  with  the  sensory  apparatus.  In  connection 
with  its  own  complex  and  delicately  adjusted  activity,  it 
calls  into  action  either  slightly  or  extensively  the  imaging 
and  perceptual  apparatus.  The  excitation  of  the  symbol 
apparatus  is  almost  as  necessary  to  conceptual  activity  as 
is  the  excitation  of  sense  and  motor  centers  to  perceptual 
activity.  In  proportion  as  the  symbol  apparatus  is  active 
in  connection  with  the  conceptual  it  is  unnecessary  that 
the  imaging  apparatus  shall  be  active  in  the  process  of 
thinking. 

PHYSIOLOGICAL  MECHANISM  OF  ATTENTION  AND  THOUGHT 

Attention  in  animals  and  in  men  may  be  regarded  as  a 
process  by  which  the  direction  of  activity  is  determined. 
The  direction  of  activity  is  determined  in  part  by  stimuli 
in  a  way  analogous  to  that  by  which  the  movements  of 
bodies  acted  upon  by  several  forces  are  directed  according 
to  the  law  of  the  resultant  of  forces.  In  physiological 
activity,  however,  the  guidance  applies  not  only  to  the  move- 


STRUCTURES  CONCERNED  IN  COMPLEX   BEHAVIOR     163 

mcnt  made  at  the  time  but  to  the  way  in  which  combined 
and  successive  movements  are  unified  so  as  to  accomplish 
the  definite  end.  In  this  respect  attention  may  be  com- 
pared to  the  movements  of  a  sailboat  under  the  influences 
of  wind  and  water.  The  analogy  is  not  complete,  how- 
ever, without  supposing  that  the  boat  moves  toward  some 
definite  point  in  response  to  adjustments  of  a  rudder. 

The  behavior  of  the  starfish  in  turning  itself  over  will 
serve  to  illustrate  the  fundamental  character  of  attention 
in  its  simplest  form,  considered  physiologically.  Each 
arm  may  work  independently  for  a  while,  but  when  a  cer- 
tain mode  of  righting  begins,  all  the  arms  modify  their 
activity  in  such  a  way  as  to  help  in  effecting  the  turning 
in  this  way,  rather  than  in  some  other  way  such  as  might 
be  used  at  another  time.  Not  only  does  the  mode  of  per- 
forming an  act  involve  a  unification  of  several  activities, 
but  the  end  to  be  gained  unifies  action  in  one  direction 
rather  than  in  another. 

When  an  animal  is  seeking  food,  the  direction  of  activity 
is  determined  by  the  end,  that  of  securing  food.  If  he  is 
fleeing  from  danger,  much  of  the  same  apparatus  may  be 
used,  but  unified  in  a  different  way.  Under  certain  cir- 
cumstances it  may  be  uncertain  for  a  time  whether  an  ani- 
mal will  eat  the  food  that  is  before  him,  flee  from  an  enemy 
that  is  approaching,  or  attack  the  enemy;  but  in  either 
case,  the  direction  of  activity  having  been  determined, 
the  activity  of  all  parts  is  unified  and  directed  by  the  end 
to  be  gained.  Stimuli  which  in  the  attainment  of  one 
end  would  seem  to  dominate  the  action  would,  in  attaining 
another  end,  have  little  or  no  influence. 

Attention  as  a  mental  process  is  the  conscious  correlate 


l64  GENETIC   PSYCHOLOGY 

of  such  acts  of  unified  behavior.  It  is  clear  that  such  a 
process  must  involve  on  the  physiological  side  enforcement 
of  certain  activities  and  inhibition  of  others.  In  creatures 
with  a  highly  developed  nervous  system  the  influence  of 
the  activity  of  one  part  upon  the  activity  of  other  parts 
is  greater  and  more  general  than  it  is  in  the  lower  animals. 

The  closeness  of  relation  of  parts  in  man  is  well  illus- 
trated by  experiments  upon  the  tendon  reflex.  When  the 
leg  is  crossed  and  the  tendon  just  below  the  knee  cap  is 
struck,  the  foot  kicks  in  an  entirely  involuntary  way.  It 
is  found,  however,  that  the  extent  of  the  kick  is  influenced 
by  other  stimuli  given  at  the  same  time,  by  any  movement 
that  may  be  made  by  the  subject,  such  as  clenching  the 
hand,  and  by  mental  processes,  such  as  addition.  Ex- 
periments also  show  that  the  amount  of  the  influence, 
and  whether  it  shall  be  positive  or  negative,  varies  accord- 
ing to  the  time  elapsing  between  the  receiving  of  another 
stimulus,  or  the  execution  of  a  movement,  and  the  stroke 
upon  the  tendon.  If  this  simple  movement  is  influenced 
by  the  activity  that  is  taking  place  in  the  sensory,  motor, 
imaging,  and  conceptual  centers,  it  would  seem  reasonable 
to  suppose  that  the  activity  of  every  nerve  center  influences 
to  some  extent  the  activity  of  every  other  nerve  center. 

It  is  not  to  be  supposed,  however,  that  the  activities  in  all 
parts  of  the  nervous  system  are  affected  to  the  same  extent. 
The  native  structure  of  the  nervous  system  is  such  that 
some  parts  are  more  closely  related  than  other  parts.  The 
nervous  system  is  also  modified  by  its  activities  so  that 
parts  which  were  not  naturally  closely  related  come  to 
exercise  a  strong  influence  upon  each  other,  while  those 
naturally   related   may   have   their   influence   upon   each 


STRUCTURES  CONCERNED  IN  COMPLEX   BEHAVIOR     165 

other's  activity  decreased.  In  general,  those  that  have 
acted  together  recently  and  repeatedly  with  favorable 
results  are  likely  to  inlluence  each  other  most.  This  is 
the  basis  of  the  general  laws  of  habit  and  association  and 
of  development  of  attention. 

We  may  conceive  of  activity  in  one  part  of  the  nervous 
system  affecting  activity  in  every  other  part,  but  in  some 
parts  earlier  and  to  a  greater  extent  than  in  others.  When 
a  number  of  parts  are  made  acti\'c  by  several  diverse  stim- 
uli and  by  the  activity  of  motor  centers,  the  direction  of 
activity  will,  in  a  general  way,  be  the  resultant  of  the 
various  influences.  When  the  activity  once  takes  a  cer- 
tain direction,  the  activity  of  one  part  is  increased  while 
that  of  others  is  decreased  in  such  a  way  that  the  tendency 
is  toward  a  definite  end  to  which  each  part  contributes. 

In  experiments  upon  the  ner\-ous  systems  of  animals 
it  is  found  that  nervous  impulses  spread  most  readily  to 
corresponding  nerve  centers  on  the  other  side  of  the  body. 
In  a  frog,  for  example,  if  one  hind  leg  is  stimulated  and 
the  stimulus  continued,  the  other  hind  leg  will  be  moved 
also.  In  the  case  of  a  dog,  which  uses  a  hind  leg  alter- 
nately with  a  front  leg,  the  stimulus  applied  to  the  hind 
leg  affects  the  fore  leg  on  the  other  side  of  the  body  be- 
fore it  does  the  other  hind  leg. 

In  experiments  upon  attention  in  which  an  object  that 
may  be  seen  in  two  ways  is  presented,  it  is  first  seen  in  one 
way,thenin  another.  This moreor  less rhythmicchange  of 
attention  is  i)robably  due,  in  j)art  at  least,  to  changes  in  the 
blood  supply  and  to  fatigue.  The  rhythm  of  attention  can, 
however,  be  greatly  modified  by  changes  in  sensations  or 
in  ideas.     Where  a  figure  is  seen  alternately  as  concave 


l66  GENETIC   PSYCHOLOGY 

and  convex  its  perception  as  a  convex  figure  may  be  pro- 
longed by  emphasizing  certain  lines  by  moving  them 
slightly,  or  by  forming  images  or  thinking  of  the  properties 
of  convex  figures,  and  by  the  utterance  of  the  word  "con- 
vex." In  a  similar  way  the  time  during  which  the  figure 
is  seen  as  concave  may  be  prolonged. 

The  difference  between  the  attention  of  men  and  of 
animals  is  chiefly  in  the  fact  that  the  attention  of  animals  is 
determined  by  sensory  stimulations  either  from  without  or 
within  the  body,  and  by  movements;  while  the  attention 
of  man  is  determined  only  in  part  by  sensory  stimuli, 
the  activity  of  imaging  and  conceptual  centers  having  a 
greater  influence  than  the  activity  of  the  sensory  and  motor 
centers.  In  trained  adults  these  centers  exercise  much 
more  influence  than  in  children  and  uneducated  adults. 

The  analysis  of  a  situation  into  elements  always  involves 
attention  and  is  usually  initiated  and  accompanied  by  some 
kind  of  instinctive  or  acquired  interest.  Most  concepts  are 
formed  by  bringing  a  number  of  these  analyzed  elements 
into  relation  with  each  other  in  the  satisfaction  of  some 
kind  of  a  need.  It  follows  therefore  that  concepts  and  at- 
tention are  necessarily  closely  related  to  each  other.  No 
grouping,  analyzing,  or  connected  thinking  is  possible  with- 
out acts  of  attention  and  feelings  of  interest,  by  means  of 
which  the  elements  are  related  to  each  other  and  unified 
in  their  relation  to  an  end.  We  should  expect,  therefore, 
to  find  the  apparatus  concerned  in  the  formation  of  con- 
cepts and  in  the  direction  of  attention  closely  connected, 
if  not  to  a  considerable  extent  the  same,  and  that  increase 
or  decrease  in  either  the  power  of  generalizing  or  attending 
would  be  accompanied  by  a  corresponding  increase  or 


STRUCTURES  CONCERNED  IN  COMPLEX   BEHAVIOR     167 

decrease  in  the  other  power.  Observation  of  faih'nf^ 
mentality  in  a  human  being  supports  this  view. 

Injuries  to  the  frontal  lobes  in  both  animals  and  men 
are  found  to  interfere  seriously  with  the  power  of  attention 
and  the  unified  activity  of  the  other  parts  of  the  brain, 
especially  in  the  performance  of  non-habitual  processes. 

The  most  extreme  ideas  have  been  held  regarding  the 
specialization  and  localization  of  function  in  the  cortex. 
Some  experimenters  find  evidence  of  very  definite  and 
specific  localization  of  function  in  the  cortex  of  men  and 
animals.  Others  produce  equally  strong  evidence  that 
the  cortex  always  functions  as  a  whole.  It  would  seem, 
from  the  preceding  discussion,  that  both  may  be  right  in 
the  main.  Although  each  portion  of  the  cortex  may  have 
a  very  definite  and  highly  specialized  function  to  perform, 
yet  even  the  simplest  processes  involve  the  associated 
activity  of  so  many  parts  of  the  brain,  and  the  activity  of  one 
part  is  so  greatly  influenced  by  the  activity  of  other  parts, 
and  all  are  so  modified  and  unified  in  the  directing  of 
activity  in  a  certain  way  by  the  process  known  as  attention, 
that  there  is  also  truth  in  the  statement  that  the  brain 
functions  as  a  whole  rather  than  as  separate  parts. 

This  is  the  usual  normal  condition  of  the  brain.  In 
pathological  cases  this  correlated  activity  in  all  parts  of  the 
brain  is  disturbed.  In  that  form  of  insanity  due  to  fixed 
ideas,  certain  centers  exert  an  undue  influence  and  deter- 
mine the  direction  of  mental  activity  whatever  may  be  the 
external  conditions  and  in  spite  of  all  attempts  to  arouse  to 
vigorous  action  other  conceptual  centers  that  ordinarily 
play  an  important  part  in  directing  mental  activity.  In 
cases  of  double  personality  there  seems  to  be  a  disassocia- 


l68  GENETIC    PSYCHOLOGY 

tion  of  one  system  of  connections  from  the  others,  so  that 
each  system  is,  in  the  main,  independent  of  the  others,  and 
the  states  of  consciousness  corresponding  to  the  activity  of 
each  system  have  little  or  nothing  in  common.  In  such  a 
case  the  sensory  motor  mechanism  may  function  equally 
well  with  either  system,  or  more  perfectly  with  one  than 
with  the  other. 

REFERENCES 

*Angell.     Psychology,  Chapter  II. 

Barker.     The  Nervous  System. 

Bastian.     Aphasia  and  other  Speech  Defects. 

*Carus,  p.     The  Soul  of  Man,  pp.  107-218. 

Collins,  Joseph.     The  Faculty  of  Speech. 

Donaldson,  H.     Growth  of  the  Brain. 

Ferrier.     Functions  of  the  Brain. 

Franz,  S.  I.     On   the  Functions  of  the  Cerebrum:    The  Frontal 

Lobes,  Archives  of  Psych.,  No.  2. 
James.     Psychology,  Chapters  VII,  VIII,  IX. 
*JuDD.     Psychology,  Chapter  III. 

LoEB.     Physiology  of  the  Brain,  Chapters  XV,  XVI,  XVII,  XVIII. 
LoESER,  Wilhelm,  M.D.     a  Study  of  the  Functions  of  Different 

Parts  of  the  Frog's  Brain,  Jr.  Comp.  Neti.  df  Psych.,  Vol.  XV, 

PP-  355-373- 

*Meyer,  M.  Nervous  Correlate  of  Pleasantness  and  Unpleasantness, 
Psych.  Rev.,  Vol.  XV,  pp.  207-216,  292-322. 

*PiLLSBURY.      Psychology  of  Attention,  Chapters  XVI  and  XV. 

Sherington,  Chas.  S.  The  Integrative  Action  of  the  Nervous 
System. 

*SlDis,  B.  The  Doctrine  of  Primary  and  Secondary  Sensory  Ele- 
ments.    Psych.  Rev.,  Vol.  XV,  pp.  44-68,  106-121. 

Are  there  Hypnotic  Hallucinations?  Psych.  Rev.,  Vol.  XIII, 

pp.  239-257. 

An  Inquiry  into  the  Nature  of  Hallucinations,  Psych.  Rev.,  Vol. 

XI,  pp.  15-29,  104-137- 

*Thorndike.     Elements  of  Psychology,  Chapters  IX,  X,  XL 


CHAPTER   VII 
CONSCIOUSNESS 

OBJECTIVE     TESTS     OF     INTELLIGENCE     AND     CRITERIA    OF 
CONSCIOUSNESS 

Up  to  this  point  we  have  described  behavior  and  mental 
processes  as  far  as  possible  in  objective  terms.  From 
this  point  on  we  are  to  give  more  attention  to  the  conscious 
states  themselves.  After  a  preliminary  consideration  of 
the  tests  and  objective  indications  of  consciousness  we 
shall  reverse  our  point  of  view,  and  starting  with  the  facts 
obtained  by  introspection  attempt  to  infer  from  our  own 
mental  states  what  the  mental  states  of  less  highly  developed 
minds  may  be.  The  standards  for  judging  intelligence 
are  similar  to  the  criteria  of  consciousness ;  hence  the  two 
may  be  considered  under  one  heading. 

We  have  direct  knowledge  of  our  own  consciousness 
only.  We  infer  that  other  beings  are  conscious.  The 
basis  for  our  inference  is  that  they  are  similar  (i)  in  struc- 
ture, and  (2)  in  behavior. 

I.  As  to  structure,  importance  is  usually  attached  not 
so  much  to  form  of  body  as  to  the  possession  of  a  certain 
kind  of  structure,  i.e.  nervous  tissue,  with  which  conscious- 
ness is  usually  supposed  to  be  associated.  Injuries  to  the 
nervous  structure  in  man  produce  more  disturbance  in 
consciousness  than  injuries  to  any  other  portion  of  his 
body.     It  is  often  thought  that  where  there  are  no  nerves 

169 


lyo  GENETIC   PSYCHOLOGY 

there  can  be  no  consciousness,  and  hence  that  animals 
without  any  nervous  structure  must  be  without  conscious- 
ness. This  view  may  be  correct,  but  the  possibility  of 
consciousness  existing  where  there  is  no  nervous  structure 
must  be  admitted.  There  is  digestion  without  any  special- 
ized organs  of  digestion  in  the  lower  forms  of  animal  life, 
and  for  aught  we  know  there  may  be  consciousness  in 
creatures  possessing  no  nervous  system. 

This  does  not  mean,  however,  that  they  have  a  conscious- 
ness like  our  own.  It  is  utterly  improbable  that  creatures 
possessing  a  nervous  system  of  a  very  simple  kind,  without 
any  specialized  sense  organs  and  without  a  complex  mo- 
tor apparatus,  have  mental  states  with  any  more  than  a 
slight  similarity  to  our  own.  Definite  specialized  states 
of  consciousness  are  probably  found  only  in  animals  having 
a  highly  specialized  sensory  and  muscular  structure,  with 
a  nervous  system  closely  relating  each  part  with  every 
other   part. 

The  habit  of  thinking  of  other  beings  as  conscious  tends 
to  make  us  ascribe  consciousness  to  the  behavior  of  crea- 
tures much  lower  than  ourselves;  but  the  whole  physical 
structure  of  a  fly,  a  clam,  and  an  amoeba  is  so  different 
from  our  own  that  w^e  have  no  reason,  on  the  basis  of  struc- 
ture only,  to  suppose  that  they  have  a  consciousness  like 
ours.  Similarity  in  the  structure  of  the  nervous  system 
would  give  us  reason  to  think  there  is  much  in  common  in 
the  consciousness  of  man,  monkeys,  dogs,  and  birds;  and 
yet,  because  of  the  larger  brain  of  man  and  the  larger 
amount  of  modifiable  nervous  material  in  his  cortex,  it  is 
probable  that  he  has  many  states  of  consciousness  entirely 
impossible  to  them. 


coNsciouSiSrEss  171 

II.  The  basis  of  inference  regarding  consciousness  of 
other  creatures  most  depended  upon  by  scientists  and 
others,  is  that  of  behavior.  Similar  behavior  is  usually 
supposed  to  be  accompanied  by  similar  states  of  conscious- 
ness, especially  when  the  creatures  comjjared  are  similar 
in  their  general  form  and  structure.  From  the  purely 
objective  point  of  view,  behavior  is  supposed  to  indicate 
consciousness  and  intelligence  according  as  it  involves 
certain  essential  characteristics.  The  characteristics  that 
have  been  named  as  indications  of  consciousness  are; 
(i)  discrimination,  (2)  motion,  (3)  purpose,  (4)  modi- 
fiability. 

(i)  It  is  not  safe  to  say  that  any  creature  has  conscious- 
ness simply  because  it  is  able  to  discriminate  differences, 
since  this  is  a  characteristic  of  inorganic  as  well  as 
organic  bodies.  A  magnet  may  be  said  to  discrim- 
inate steel ;  and  every  chemical  atom  has  its  special 
affinities  which,  in  an  objective  way,  involve  discrimina- 
tion to  as  great  an  extent  as  does  the  reflex  and  instinctive 
behavior  of  animals.  There  is  no  organism,  either  plant  or 
animal,  that  does  not  discriminate  in  the  sense  of  reacting 
to  different  stimuli  in  different  ways.  It  is  true,  however, 
that  fineness  and  accuracy  of  discrimination  in  animals 
and  men  are  usually  taken  as  one  evidence  of  intelligence. 
This  however  is  not  to  be  looked  upon  wholly  as  a  charac- 
teristic of  consciousness,  but  as  dependent  upon  the  delicacy 
of  the  mechanism  with  which  the  individual  is  provided. 

The  number  of  different  discriminations  possible  is  often 
considered  a  better  measure  of  intelligence  than  fineness 
of  discrimination.  The  lower  animals  with  fewer  special- 
ized sense  organs  make  fewer  discriminations  than  do  the 


172  GENETIC   PSYCHOLOGY 

higher,  and  the  broadly  cultured  man  makes  many  dis- 
criminations unnoticed  by  the  uncultured. 

A  more  significant  fact  regarding  discrimination  is  found 
in  the  characteristic  of  discriminating  between  what  is 
favorable  and  what  is  unfavorable  to  the  organism.  All 
animals  have  something  of  this  regulative  discrimination, 
by  means  of  which  they  act  so  as  to  get  away  from  or  avoid 
unfavorable  conditions  and  so  as  to  maintain  or  secure 
favorable  ones.  This  phase  of  discrimination  cannot  be 
readily  explained  on  the  basis  of  structure  only,  neither 
is  it  certain  that  the  laws  of  physiological  equilibrium  will 
fully  explain  this  phenomenon.  Consciousness,  if  not 
absolutely  necessary,  is  doubtless  of  great  help  in  deter- 
mining the  favorable  or  unfavorable  character  of  any 
particular  stimulation.  Certain  it  is  that  we  are  more 
inclined  to  ascribe  intelligence  to  creatures  that  quickly 
and  easily  discriminate  between  w^hat  is  injuring  them 
and  what  is  for  their  good,  and  still  more  do  we  ascribe 
intelligence  to  those  that  discriminate  suggestive  stimuli 
that  are  neither  harmful  nor  helpful  in  themselves  but 
are  the  forerunners  of  favorable  or  unfavorable  stimuli 
to  follow. 

(2)  Motion  is  always  suggestive  of  consciousness,  prob- 
ably because  the  motions  which  we  notice  most  are  those 
of  persons  to  whom  we  are  in  the  habit  of  ascribing  con- 
sciousness similar  to  our  own.  When,  therefore,  we  see 
movement  in  animals  we  infer  that  there  is  consciousness 
accompanying  the  motion  and  directing  it.  This  is  prob- 
ably the  reason  why,  in  the  common  mind,  all  animals  that 
move  are  conscious,  while  plants  which  do  not  as  a  rule 
move    are    unconscious,    notwithstanding    the   fact    that 


CONSCIOUSNESS  173 

some  plants  are  more  highly  organized  than  some  animals. 
The  recent  experiments  of  Bose,  however,  have  sliown 
that  movement  which  is  supposed  to  be  exceptional  in 
plants  is  really  common.  The  movement  in  plants, 
however,  is  very  slow,  the  response  to  stimulation  occupy- 
ing minutes  where  that  of  an  animal  would  occupy  only  a 
fraction  of  a  second. 

Accuracy  of  movement  is  often  considered  an  evidence 
of  intelligence,  perhaps  because  it  is  intimately  associated 
with  discrimination.  Like  fineness  of  discrimination, 
accuracy  of  motion  is  to  be  explained  by  the  structure  of  the 
apparatus  rather  than  by  consciousness.  It  is  true  only 
in  a  general  way  and  for  certain  forms  and  grades  of  in- 
telligence that  accuracy  of  movement  is  associated  with 
greater  general  intellectual  power  either  in  animals  or 
men.  The  results  of  sensory  and  motor  tests  have  been 
found  to  correspond  to  the  judgment  of  teachers  as  to 
the  intelligence  of  small  children,  but  not  in  the  case  of 
college  students. 

Variety  of  movements  is  sometimes  considered  as  a 
better  standard  of  intelligence,  and  it  is  generally  true  that 
the  higher  animals  are  capable  of  a  much  greater  variety 
of  movement  than  the  lower,  and  man  of  a  greater  variety 
than  any  other  creature.  As  we  have  already  seen,  this  is 
due  in  part  at  least  to  the  peculiar  type  of  motor  organiza- 
tion with  which  he  is  so  highly  endowed.  Whether  such  a 
type  of  motor  mechanism  could  be  successfully  perfected 
and  operated  without  conscious  intelligence,  may  well  be 
questioned. 

A  still  more  trustworthy  standard  of  consciousness  and 
intelligence  is  \.\\q  fitness  of  the  movement  to  m.cet  the  situ- 


174  GENETIC   PSYCHOLOGY 

ation.  However  complex  and  varied,  or  however  well  it 
might  be  suited  to  some  other  situation,  a  movement  is  not 
regarded  as  evidence  of  intelligence  unless  it  meets  the 
particular  situation  in  such  a  way  as  to  bring  favorable 
results  to  the  creature.  This  standard  of  consciousness  is 
one  very  difficult  to  apply,  for  all  creatures  are  able  to 
make  fitting  movements  characteristic  of  their  species  under 
the  usual  situations,  while  in  unusual  situations  their  move- 
ments are  often  injurious  instead  of  helpful.  Similarly, 
men  of  different  training  and  habits,  each  successful  in  his 
own  field,  may  fail  completely  when  attempting  to  do  some- 
thing in  another  line  of  work  and  be  regarded  as  exceedingly 
stupid  by  the  specialist  in  that  line. 

The  higher  animals,  and  especially  man,  are  regarded  as 
more  intelligent  because  they  are  able  to  meet  and  react 
properly  to  many  changing  situations.  This  is  generally 
considered  as  one  of  the  strongest  evidences  of  intelligence, 
providing  some  definite  end  is  secured  by  the  varied  reac- 
tions to  the  new  situations. 

(3)  One  very  common  standard  for  judging  conscious 
intelligence  is  that  of  the  purposefulness  of  the  movements 
made.  Objectively,  purpose  means  simply  action  toward 
the  attainment  of  some  end,  and  many  suppose  that  where 
such  adaptation  is  shown  there  must  be  a  consciousness  of 
the  purpose  to  be  achieved.  This  view  however  cannot 
be  logically  adhered  to  unless  plants  are  supposed  to  be 
conscious  also,  for  their  growth  processes  are  very  perfectly 
adapted  to  the  ends  of  producing  seed  and  providing  for  its 
protection,  dissemination,  and  future  growth.  In  the  case 
of  animals,  purpose  is  objectively  indicated  in  their  reflex 
and  instinctive  movements,  but  the  fact  that  certain  results 


CONSCIOUSNESS  1 75 

come  through  these  movements  docs  not  prove  that  they 
are  conscious  of  acting  to  secure  those  results.  Judging 
from  our  own  reflex  movements  there  is  no  consciousness 
of  what  is  to  be  done,  but  merely  of  the  results  as  they 
occur.     The  same  is  usually  true  of  instinctive  movements. 

Variety  of  ends  toward  which  action  is  directed  is  gener- 
ally considered  indicative  of  conscious  intelligence.  The 
higher  animals  are  endowed  with  a  much  greater  variety 
of  instinctive  behavior  than  the  lower,  and  man  with  a 
still  greater  variety.  The  cultured  man  also  seeks  many 
more  ends  than  the  uncultured. 

Where  the  action  of  human  beings  is  for  remote  rather 
than  immediate  ends  we  are  more  apt  to  ascribe  intelligence. 
The  savage  provides  for  the  wants  of  to-day  and  perhaps 
to-morrow,  while  civilized  man  makes  preparations  for 
desirable  ends  years  hence.  In  the  animal  world  there 
is  no  very  close  correspondence  between  the  immediate- 
ness  or  remoteness  of  ends  toward  which  instinctive 
action  is  directed  and  the  degree  of  intelligence  of  the 
creature. 

The  suitability  of  the  end  toward  which  the  actions  are 
directed  is  always  a  basis  of  judging  of  intelligence.  Any 
creature  that  acts  to  secure  that  which  would  be  of  no  value 
to  him  is  regarded  as  lacking  in  conscious  intelligence; 
while  those  that  most  successfully  choose  that  which  is  for 
their  own  good  are  regarded  as  the  most  intelligent. 
Where  the  good  to  be  secured  corresponds  closely  to  ends 
that  are  commonly  secured  by  instinctive  action,  intelli- 
gence is  not  usually  supposed  to  be  so  great  as  where  the 
advantage  is  peculiar  to  the  individual  and  perhaps  op- 
posed to  what,  under  ordinary  circumstances,  is  good  for 


176  GENETIC   PSYCHOLOGY 

the  species.  This  would  seem  a  very  good  basis  for  infer- 
ring conscious  intelligence,  but  it  is  not  always  easy  to  tell 
whether  the  suitable  action  is  characteristic  of  the  species, 
native  to  the  individual,  or  one  based  on  individual  experi- 
ence. The  behavior  of  ants  previously  described  seems 
less  intelligent  when  we  realize  how  nearly  it  conforms  to 
the  usual  instinctive  behavior  of  the  species. 

(4)  Modifiahility,  or  the  capacity  to  be  changed  by  ex- 
perience, is  perhaps  used  more  than  any  other  standard 
tor  determining  the  presence  and  degree  of  consciousness 
possessed  by  any  creature.  It  cannot,  however,  be  taken  as 
the  absolute  standard  of  the  presence  or  absence  of  con- 
sciousness unless  we  suppose  that  all  organisms  are  con- 
scious, for  all  are  subject  to  modification  by  experience  and 
surroundings.  Plants  transplanted  from  one  latitude  to 
another  are  different  in  their  growth  from  those  grown  in 
the  same  locality,  which  shows  that  they  have  been  modified 
by  the  different  conditions  to  which  they  have  been  sub- 
jected. As  we  have  already  shown,  even  the  lowest  animals 
are  very  soon  modified  by  variations  in  light,  heat,  and 
chemical  condition  of  their  surroundings.  In  higher  ani- 
mals such  modifications  in  behavior  are  much  more 
permanent  and  more  quickly  made.  The  pigeon  can  learn 
to  pass  through  a  maze  and  obtain  food  by  the  shortest 
route  in  ten  repetitions,  while  a  crab,  to  acquire  equal 
success  in  a  simpler  maze,  needs  several  hundred. 

The  readiness  with  which  the  behavior  of  animals  is 
thus  modified  is  a  very  good  standard  of  the  degree  of  in- 
telligence that  they  possess,  providing  the  behavior  modi- 
fied in  each  case  is  equally  characteristic  of  the  species 
compared,  and  the  conditions  are  equally  suitable  to  their 


CONSCIOUSNESS  177 

mode  of  life.  The  rat  readily  learns  to  find  its  way  through 
a  maze  either  lighted  or  unlighted,  while  the  pigeon  does 
not  learn  so  readily  in  a  lighted  maze  and  still  less  readily  in 
a  darkened  one.  This  is  not  a  clear  j^roof  of  the  greater 
intelligence  of  the  rat,  because  threading  mazes  constitutes 
a  large  part  of  the  instinctive  activity  of  his  species  and 
usually  this  is  done  in  darkness,  while  threading  mazes 
is  an  exceptional  form  of  activity  to  the  pigeon  species  and 
movement  in  the  dark  very  unusual. 

Where  a  creature  not  only  readily  learns  to  do  one  thing, 
but  can  also  easily  learn  to  do  a  great  variety  of  things,  we 
have  still  more  ground  for  ascribing  to  him  intelligence. 
This  is  one  of  the  marked  distinctions  between  higher  and 
lower  animals,  and  especially  between  man  and  other 
animals.  Every  animal  is  a  specialist  in  his  instinctive 
mode  of  life,  while  man  rivals  animals  in  most  lines  of  be- 
havior, besides  engaging  in  many  imj)ossible  to  them. 

Again,  if  a  creature  learns  something  and  a  few  hours  or 
a  few  days  later  shows  no  evidence  of  having  learned  it,  he 
is  not  regarded  as  so  intelligent  as  one  who  retains  the  modi- 
fication through  a  long  period  of  time.  Whether  quickness 
of  learning  and  permanence  of  retention  arc  more  likely 
to  be  found  associated  than  in  reverse  relationship  cannot 
be  stated  with  certainty  from  what  is  known  of  these 
characteristics  in  animals  and  in  man ;  but  recent  evidence 
indicates  that  permanency  of  retention  is  more  characteris- 
tic of  species  and  individuals  that  are  easily  modified. 

The  kinds  of  modifications  that  take  place  with  refer- 
ence to  present  and  future  needs  are  also  regarded  as  indi- 
cations of  intelligence.  IVIodification  of  behavior  that  at 
no  time  brings  any  advantage  is  not  regarded  as  evidence 

N 


178  GENETIC   PSYCHOLOGY 

of  intelligence,  however  easily,  rapidly,  and  permanently 
it  may  be  made. 

Although  none  of  the  criteria  named  above,  when  taken 
alone,  is  positive  evidence  of  consciousness  or  measures 
of  intelligence,  yet  several  of  them  combined  give  a  good 
basis  for  inferring  consciousness  and  estimating  the  degree 
of  intelligence.  The  finer,  more  varied,  and  advantageous 
the  discriminations,  the  more  accurate,  varied,  complex 
and  useful  the  movements;  the  more  behavior  is  suited  to 
securing  many  and  distant  ends,  and  the  more  all  these  have 
been  the  result  of  modifications  produced  in  the  life  of  the 
individual  by  his  own  experience,  the  better  the  ground  for 
affirming  conscious  intelligence  of  a  high  degree. 

The  essential  characteristic  of  all  intelligent  action  is, 
from  the  objective  point  of  view,  that  it  shall  be  adapted 
to  the  securing  of  useful  ends.  In  this  sense  an  animal  in 
his  usual  environment  appears  to  be  intelligent  by  instinct. 
The  word  has,  however,  generally  been  used  in  a  sense  some- 
what contrasting  with  instinct,  to  designate  actions  that 
effectively  and  economically  meet  situations  that  cannot 
be  met  so  effectively  or  perhaps  at  all  by  the  usual  instinc- 
tive behavior  of  the  species.  In  the  preceding  discussion, 
however,  the  common  characteristic  in  instinctive  and 
acquired  actions  of  being  suited  to  the  attainment  of 
favorable  ends  has  been  strongly  emphasized  as  important 
in  comparisons  of  species  and  individuals.  This  broader 
use  of  the  term  intelligence  is  more  favorable  to  the  forma- 
tion of  genetic  conceptions  of  behavior  than  that  which 
narrows  the  meaning  of  the  word  to  make  it  contrast  with 
instinct.  In  later  discussions  we  shall  show  the  useful- 
ness of  this  broader  meaning. 


CONSCIOUSNESS  1 79 

SUBJECTIVE   CRITERIA   OF   CONSCIOUSNESS   AND    ITS    FUNC- 
TIONS 

Since  all  our  knowledge  of  consciousness  is  based  on  our 
knowledge  of  our  own  consciousness,  we  must  introspec- 
tively  observe  our  own  behavior  to  determine  when  con- 
sciousness is  most  intense  and  in  what  circumstances  it  is 
most  helpful,  and  from  such  observations  we  may  in- 
fer the  presence  of  consciousness  when  similar  behavior 
is  shown  by  other  creatures.  By  noticing  what  can  and 
what  cannot  be  done  without  consciousness  and  what  can 
be  done  better  with  and  without  it,  we  may  also  form  a 
better  idea  of  the  real  functions  of  consciousness. 

We  note  first  that  consciousness  is  most  prominent 
when  there  are  changes  in  situation  and  behavior,  the 
degree  of  consciousness  appearing  to  vary  with  the  rapidity 
of  the  change.  A  very  gradual  decrease  in  the  tempera- 
ture of  an  object  touching  the  skin,  or  of  the  air  or  water 
surrounding  the  whole  body,  is  scarcely  felt,  while  a  much 
smaller  change,  occurring  suddenly,  gives  a  very  distinct 
sensation.  The  gradual  dawning  or  fading  of  the  light  of 
the  sun  is  imperceptible  except  by  comparison  with  the 
memory  of  how  it  looked  a  few  moments  before;  but  the 
sudden  flashing  or  going  out  of  the  tiny  flame  of  a  match 
gives  a  very  distinct  sensation.  The  same  truth  holds  re- 
garding all  sensations  and  movements  and  also  regarding 
perceptions,  images,  and  concepts.  Their  presence  in  the 
usual  way  and  under  usual  conditions  involves  so  little 
consciousness  that  it  is  almost  impossible  to  observe 
mental  processes  sufl[iciently  to  describe  them  except  when 
they  are  in  some  way  changing  or  being  carried  on  under 


l8o  GENETIC   PSYCHOLOGY 

unusual  conditions.  The  ability  to  observe  one's  own 
mental  processes  has  to  be  cultivated.  One  reason  why 
experimental  psychology  has  led  to  the  discovery  of 
many  important  facts  in  the  course  of  the  experiments  is 
because  the  special  conditions  of  the  experiments  make  the 
conscious  processes  more  noticeable. 

The  law  of  change  is  probably  not  limited  to  conscious 
phenomena,  for  nervous  processes  usually  supposed  to  be 
unconscious  conform  to  the  same  law.  The  physiologist, 
in  his  experiments  upon  nerves  and  muscles  separated  from 
the  central  nervous  system,  finds  that  sudden  though  slight 
changes  in  the  strength  of  a  stimulus  produce  greater  reac- 
tion than  larger  but  more  gradual  changes.  A  continuous 
current  of  electricity  produces  no  reaction  at  all,  though  it 
may  modify  other  reactions,  contractions  being  made  only 
when  it  is  first  sent  in  and  when  it  is  shut  off.  The  same 
phenomenon  of  response  to  sudden  changes  in  stimuli 
is  shown  in  all  forms  of  animal  life,  including  those  without 
any  specialized  nerve  tissue,  as  is  illustrated  by  the  first 
reaction  of  a  Paramecium  to  warmer  or  colder  water. 
It  is  claimed  that  a  frog  may  be  boiled  alive  without 
struggling  if  the  water  is  heated  very  gradually.  It  is 
a  familiar  fact  that  sudden  changes  in  stimuli  keep  one 
awake,  while  continuous  and  monotonous  stimuli  often 
produce  sleepiness. 

Turning  now  to  the  various  forms  of  activity  we  find  that 
the  physiological  processes  of  respiration,  circulation,  and 
digestion  are  usually  performed  without  sudden  changes 
and  without  consciousness.  If  air,  food,  or  other  conditions 
are  changed,  so  that  great  and  sudden  variations  in  these 
processes  occur,  as  when  the  air  is  shut  off  or  gas  is  taken, 


CONSCIOUSNESS  l8l 

or  when  poisonous  drugs  or  excessive  amounts  of  food  are 
taken,  consciousness  becomes  intense.  Reflex,  instinctive, 
and  habitual  movements,  such  as  winking,  walking,  and 
dressing  in  the  usual  way  under  usual  conditions  also  have 
little  conscious  accompaniment ;  but  we  become  acutely 
conscious  of  any  interference  with  these  activities.  The 
details  of  nearly  all  familiar  voluntary  movements  also 
have  little  place  in  consciousness,  which  is  usually  occupied 
with  the  new  phases  of  the  situation  which  vary  with  each 
performance.  If  the  situation  and  modes  of  performance 
remain  the  same  the  act  soon  becomes  an  unconscious  habit. 
It  seems  therefore  that  consciousness  has  no  part  in  physio- 
logical, reflex,  and  instinctive  behavior  common  to  the 
species  except  as  these  processes  are  modified  by  the  special 
experiences  of  the  individual,  and  also  that  acquired  modes 
of  behavior  almost  or  entirely  cease  to  be  conscious  when 
they  become  uniform. 

Since  the  changes  producing  intensity  of  consciousness 
may  be  primarily  either  in  the  external  stimulation  or 
condition  or  in  changes  in  the  mode  of  action  of  the  organs 
responding,  we  need  to  notice  the  role  of  consciousness  in 
each  case.  In  walking  in  the  habitual  way,  consciousness 
is  prominent  only  when  we  meet  with  obstructions  or 
unusual  variations  in  the  surface.  A  child's  first  move- 
ments of  every  type  doubtless  produce  conscious  states, 
for  they  are  producing  changes  in  his  nervous  system  ;  but 
they  certainly  are  not  directed  by  consciousness.  In 
combining  mo\ements  in  various  series  and  reacting  to  the 
constantly  varying  phases  of  environment  there  is  continual 
occasion  for  and  need  of  consciousness. 

As  we  have  already  seen  in  the  process  of  learning,  even 


l82  GENETIC   PSYCHOLOGY 

when  external  conditions  remain  uniform,  there  is  consider- 
able variety  in  the  way  in  which  a  thing  is  done  until  some 
one  mode  of  reaction  is  perfected  and  established  as  a 
habit.  This  means  of  course  that  the  parts  concerned  are 
being  modified  during  the  learning  process.  Such  modifica- 
tion is  doubtless  a  stronger  stimulus  to  consciousness  than 
mere  variation  in  objective  stimulation. 

Where  the  changes  in  the  situation  are  such  as  have 
been  frequently  reacted  to  in  the  same  way  they  may 
occur  almost  without  consciousness  even  in  a  complex 
series.  A  striking  example  of  this  is  shown  when  a  per- 
son reading  aloud  and  thinking  of  something  else  per- 
forms the  very  complex  mental  operation  of  perceiving 
all  the  different  words  and  speaking  them  in  the  proper 
order  and  perhaps  with  fairly  good  inflection.  When, 
however,  the  act  involves  the  reaction  to  a  new  situation 
or  a  modification  in  the  mode  of  reaction,  even  a  very 
slight  change,  such  as  a  new  pronunciation  of  a  word, 
demands  a  considerable  degree  of  consciousness.  Again, 
while  one  could  walk  a  long  distance  climbing  stairs  and 
making  various  turns  almost  without  consciousness  of  the 
complex  but  familiar  adjustments  involved,  it  would  re- 
quire his  whole  attention  to  learn  a  new  movement,  such 
as  a  step  in  dancing. 

It  is  evident,  therefore,  that  the  acts  accompanied  by 
most  consciousness  are  those  involving  the  functioning  of 
new  apparatus  or  the  functioning  of  formerly  used  appara- 
tus in  new  ways,  while  a  change  from  using  one  apparatus 
to  using  another,  if  the  transition  is  a  habitual  one,  may 
be  almost  without  consciousness. 

There  is  therefore  good  reason  for  saying  that  since 


CONSCIOUSNESS  1 83 

consciousness  is  especially  i)rominent  in  all  new  reactions 
it  is  probably  most  prominent  in  the  actions  of  animals 
which  are  able  to  learn  most  by  experience,  or,  in  other 
words,  in  animals  whose  nervous  system  is  subject  to  the 
greatest  amount  of  modification. 

It  is  not  true  however  that  no  modification  of  the  nervous 
system  can  take  place  without  consciousness.  Very  great 
changes  may  thus  take  place  if  they  are  sufficiently  gradual. 
We  find  this  to  be  true  of  a  large  number  of  physical  and 
mental  habits  which  develop  or  change  without  our  knowing 
it  until  our  attention  is  called  to  the  matter  by  some  friend 
or  by  some  event  that  makes  us  recall  what  we  used  to  do 
under  the  same  circumstances.  The  same  thing  is  shown 
in  a  striking  way  by  a  series  of  experiments  made  by  Pro- 
fessor Judd  upon  a  common  illusion  regarding  the  length  of 
lines.  The  subjects  who  were  attempting  to  reproduce  the 
lines  shown  them  did  not  know  that  they  were  making  an 
error ;  but  after  many  hundreds  of  experiments,  the  error, 
which  at  first  had  been  very  great,  was  reduced  almost  to 
zero.  Other  experiments  have  shown  that  when  a  subject 
knows  that  he  is  making  an  error  and  is  told  each  time  its 
character  and  amount,  he  corrects  it  much  more  quickly 
than  when  he  has  no  definite  knowledge  of  the  results  of 
his  attempts.  Evidently,  therefore,  consciousness  is  not 
absolutely  necessary  in  producing  helpful  modifications  in 
behavior,  yet  modification  of  behavior  without  directive 
consciousness,  like  trial  movements,  is  a  very  uneconomical 
mode  of  i)rocedure.  Consciousness,  therefore,  if  not  in- 
volved in  all  modifications,  is  at  lea^t  a  means  to  more 
rapid  and  efficient  modifications  of  behavior,  and  hence  is 
probably  present  in  all  animals  capable  of  rapid  learning. 


l84  GENETIC    PSYCHOLOGY 

Teachers  should  remember  that  when  children  know  the 
end  for  which  they  are  working  and  are  aware  of  the  prog- 
ress that  they  are  making,  they  will  learn  much  more 
rapidly  than  when  they  are  simply  told  what  they  must  do 
and  how  it  must  be  done  without  being  made  conscious 
of  the  success  of  their  attempts. 

Observing  a  little  more  closely  our  mental  processes 
when  acquiring  a  new  movement  or  attempting  to  solve  a 
problem,  we  notice  that  consciousness  in  all  instances  is 
not  concerned  so  much  with  the  act  of  doing  as  with  the 
results  of  the  act.  For  example,  in  reproducing  a  drawing, 
as  we  try  again  and  again,  consciousness  tells  us  of  the  re- 
sult rather  than  of  the  movements  made.  The  same  is  true 
in  articulation  of  words,  learning  to  skate,  in  manual  occu- 
pations of  all  kinds,  and  also  in  the  more  purely  mental 
activities  of  seeking  a  solution  of  a  problem  in  mathematics, 
and  in  writing  a  satisfactory  composition  or  article. 

Consciousness,  however,  is  not  concerned  simply  with  the 
result  of  individual  movements  or  series  but  with  the  end 
toward  which  we  are  aiming  and  the  relation  of  the  results 
of  each  act  to  that  end.  This  is  often  shown  in  the  feeling 
that  we  are  progressing  toward  an  end  even  when  we  do 
not  know  just  what  we  are  doing  that  is  helping  us  toward 
that  goal.  We  feel  that  we  are  getting  the  mastery  of  a 
tool  or  of  a  topic  without  knowing  in  just  what  way  we  are 
changing  our  activity. 

The  relating  of  means  to  ends  is  not  however  in  all  prob- 
ability a  purely  conscious  process,  but  is  characteristic  of  all 
organic  activity.  As  we  have  already  seen,  what  an  animal 
even  of  the  lowest  type  does  after  reacting  to  a  stimulus 
depends  upon  whether  the  result  of  the  previous  action  is 


CONSCIOUSNESS  185 

favorable  or  unfavorable.  If  such  creatures  have  any 
consciousness  it  must  be  in  the  primitive  and  vague  form 
of  an  indefinite  feeling  of  dissatisfaction  or  of  satisfaction. 
If  consciousness  is  of  any  value  whatever  to  such  creatures 
it  must  be  because  this  feeling  produces  a  change  of  action 
when  the  results  are  unfa\orable.  When  consciousness 
appears  it  must  perform  this  function  and  thus  facilitate  the 
proper  reaction. 

We  may  say,  therefore,  that  the  primary  function  of 
consciousness  in  the  evolution  of  behavior  is  to  emphasize 
the  results  of  an  action  with  reference  to  the  end  to  be  ob- 
tained. 

Again  we  note  the  fact  that  consciousness  is  most  in- 
tense, not  when  we  are  trying  to  achieve  some  one  end 
by  a  certain  means  but  when  we  are  doubtful  as  to  which 
of  two  or  more  ends  we  shall  attempt  to  gain,  or  as  to 
which  of  several  means  we  shall  use.  Evidently,  where 
there  is  a  tendency  to  react  to  several  stimuli  in  varied  and 
perhaps  opposite  ways,  the  difficulty  of  making  a  reaction 
which  is  of  advantage  to  the  organism  as  a  whole  is  very 
much  increased.  It  is  in  just  such  cases  therefore  that 
consciousness  may  be  of  the  most  assistance.  If,  to  its 
power  of  emphasizing  the  results  of  action  with  reference 
to  an  end,  be  added  the  power  to  emphasize  one  result  with 
reference  to  one  end  rather  than  to  any  other,  we  have  a 
second  important  function  of  consciousness  which  may  be 
designated  as  its  selective  function,  which  of  course  in- 
volves discrimination  and  comparison  and  is  especially 
manifested  in  acts  of  attention. 

In  order  that  consciousness  may  thus  effectively  direct 
behavior  it  is  necessary  that  it  shall  be  occupied  with  some- 


l86  GENETIC   PSYCHOLOGY 

thing  besides  the  results  of  present  stimulation.  To  act 
effectively  it  must  be  able  to  represent  the  results  of  past 
stimulations  and  reactions  in  order  that  the  end  and  the 
means  of  reaching  it  may  be  selected.  The  more  per- 
fectly the  elements  of  past  experience  may  be  reproduced 
and  freed  from  the  connections  in  which  they  formerly 
occurred,  so  as  to  be  combined  into  representations  of 
results  and  of  means  of  obtaining  them,  the  greater  the 
possibility  of  consciousness  directing  action  in  many  and 
varied  ways.  The  ability  to  form  free  images,  which  is 
closely  correlated  with  the  tendency  to  imitate  new  move- 
ments, is  necessary  to  any  considerable  use  of  conscious- 
ness in  directing  new  reactions. 

If  this  is  true,  the  part  played  by  consciousness  in  direct- 
ing the  actions  of  animals  in  the  performance  of  new  acts 
must  be  very  small  even  in  the  case  of  the  most  intelligent. 
The  chief  way  in  which  consciousness  helps  them  to  learn 
is  in  emphasizing  results  after  the  act  has  been  performed, 
thus  increasing  the  tendency  to  act  in  the  same  way  again 
if  the  results  are  favorable,  and  decreasing  it  if  they  are  not. 

Consciousness  in  animals  is  probably  concerned  chiefly 
with  results  as  they  occur  rather  than  with  the  various  ones 
that  may  appear  after  the  action  is  performed.  For  ex- 
ample, the  dog  that  was  cold  and  went  to  his  mistress's  door 
and  pawed  until  she  came  and  covered  him,  was  doubtless 
directed  more  by  the  present  feeling  of  being  cold  than  by 
a  representation  of  being  warm.  It  is  also  probable  that 
the  animal  did  not  first  represent  various  means  of  getting 
rid  of  the  disagreeable  feeling  and  then  select  the  one  of 
going  to  the  mistress's  door  and  pawing,  instead  of  any 
other,  but  it  performed  that  act  because  in  past  experience 


CONSCIOUSNESS  187 

the  tendency  to  go  to  his  mistress  when  uncomfortable  had 
been  increased  by  the  favorable  results  of  such  action. 

It  is  evident  from  the  preceding  discussion  that  although 
all  organisms  possess  unity,  and  all  their  activity  is  unifying, 
yet  that  consciousness  is  helpful  in  coordinating  activities 
when  they  are  many  and  varied  so  as  to  make  them  all 
contribute  to  one  end.  To  unify  and  coordinate  in  rela- 
tion to  an  end  may  therefore  be  considered  as  the  third 
and  most  important  function  of  consciousness.  This 
function  involves  to  some  extent  the  other  two,  the  feeling 
of  the  results  of  activity,  and  the  selection  of  some  activities 
for  continuance. 

We  have  in  these  functions  of  consciousness  the  basis  for 
the  common  classification  of  mental  facts  into  three  divi- 
sions: feeling,  intellect,  and  will.  In  its  elementary  form, 
consciousness  is  a  mere  feeling  which  indicates  whether 
reaction  is  needed  or  not.  In  its  next  higher  form  of 
intellect  it  discriminates  ends  to  be  reached  and  the  means 
by  which  they  may  be  gained,  while  in  the  act  of  choosing, 
enforcing,  and  harmonizing  activities  in  the  attainment  of 
ends  we  have  the  phenomenon  of  conscious  ivilling. 

In  order  that  consciousness  may  function  effectively  in  an 
intellectual  and  volitional  way  it  is  necessary  that  there 
shall  be  not  only  sensory  apparatus  to  present  to  conscious- 
ness the  effects  of  stimulation,  and  a  motor  apparatus  to 
execute  movement,  but  there  must  be  a  central  nervous 
structure  by  means  of  which  the  results  of  past  experiences 
may  be  represented  in  consciousness  and  the  [possible  re- 
sults of  future  actions  presented.  As  we  have  already  seen, 
such  additional  nervous  structures  are  provided  in  the  cor- 
tex of  man  to  a  much  greater  extent  than  in  that  of  any 


l88  GENETIC   PSYCHOLOGY 

Other  animal.  Such  mechanisms  for  reproducing  the 
resuhs  of  past  experience  and  directing  new  combinations 
must  not  only  be  present,  but  must  have  been  trained  in 
order  that  consciousness  may  function  effectively.  Just  as 
a  general  must  not  only  have  men  but  must  organize  and 
train  them  in  all  the  activities  of  warfare,  so  must  a  crea- 
ture whose  consciousness  works  effectively  have  not  only  a 
modifiable  nervous  apparatus  but  this  apparatus  must  be 
properly  organized. 

Consciousness  helps  in  directing  the  organization  of 
nervous  structure,  and  then  after  such  structure  has  be- 
come well  organized,  it  uses  it  in  various  complex  activities 
without  directing  in  detail  what  shall  be  done.  Injury 
to  the  sensory,  motor,  or  representative  apparatus  usually 
involved  in  an  act  may  leave  consciousness  helpless  so  far 
as  the  performance  of  that  act  is  concerned.  In  some 
instances,  however,  consciousness  may  train  other  nerve 
centers  to  perform  the  acts  of  that  which  has  been  injured, 
as  when  one  who  has  lost  the  power  of  movement  in  the 
right  arm  trains  the  nerve  centers  governing  the  left  arm 
to  direct  similar  movements,  or  when  visual  centers  are 
injured  and  auditory  images  are  substituted  in  memory 
and  thinking. 

In  racial  development  consciousness  in  the  form  of 
rudimentary  feeling  indicating  the  necessity  or  non- 
necessity of  movement  may  be  present  momentarily  even 
in  the  lowest  organisms  and  help  to  produce  more  prompt 
and  effective  reactions.  In  the  case  of  larger  animals  with 
various  sensory-motor  structures  such  a  consciousness 
corresponding  to  favorable  or  unfavorable  relations  of  all 
parts  would  surely  be  useful,  if  not  absolutely  necessary. 


CONSCIOUSNESS  1 89 

It  is  also  necessary  in  such  creatures  that  there  shall  be 
a  large  amount  of  modifiable  nervous  tissue  if  directive 
control  by  consciousness  is  to  be  acquired. 

Consciousness  as  a  mere  feeling  may  help  to  unify  the 
various  processes  taking  place  in  a  complex  organism, 
but  consciousness  as  a  discriminative  and  representative 
process  is  especially  needed  in  unifying  not  simply  present 
activities  but  present  and  past  experiences  in  relation  to 
each  other  and  a  possible  future.  The  great  function  of 
consciousness  in  all  its  forms  is  to  help  unify  behavior  by 
"dislocating  experiences,"  as  Minot  puts  it,  from  their  set- 
ting, thus  making  single  elements  of  several  past  experiences 
combine  for  the  good  of  the  creature  in  the  present  and  for 
the  future.  In  its  higher  forms,  as  exhibited  in  man,  it  is 
chiefly  concerned  with  bringing  together,  connecting,  and 
unifying  the  results  of  past  experience  in  relation  to  future 
ends  rather  than  in  relating  the  activities  to  present  con- 
ditions only.  Just  as  consciousness  may  be  helpful  in  co- 
ordinating new  movements  in  the  present  so  it  is  still  more 
helpful  in  coordinating  the  actions  of  to-day  with  those  of 
yesterday  and  to-morrow. 

Consciousness  may  very  well  be  regarded  as  a  more 
eflicient  and  economical  means  of  performing  in  the  life 
of  the  individual  wliat  in  the  life  of  the  species  is  effected 
by  means  of  natural  selection.  Natural  selection  proceeds 
by  the  very  wasteful  method  of  killing  off  all  individuals  of 
the  species  whose  actions  are  least  effective,  while  conscious- 
ness in  the  individual,  by  means  of  feelings  of  pain,  elimi- 
nates ineffective  movements  and  causes  more  economical 
ones  to  be  selected  for  repetition  and  thus  to  become 
established  as  habits.     By  means  of  pleasurable  feelings, 


190 


GENETIC    PSYCHOLOGY 


eflfective  modes  of  reaction  are  more  quickly  established 
than  would  otherwise  be  the  case.  Consciousness  thus 
differs  from  natural  selection  in  being  a  positive  as  well  as 
a  negative  factor  in  modifying  behavior. 

In  its  higher  forms  consciousness  selects  not  only  accord- 
ing to  results  that  have  just  been  experienced,  but  also  to 
results  of  more  remote  experiences;  and  selects,  not  blindly 
but  intelligently,  by  means  of  conscious  representation  of 
the  ends  to  be  gained  and  the  means  to  be  used.  So  effec- 
tive is  consciousness  in  directing  the  evolution  of  behavior 
that  it  produces  in  the  lifetime  of  a  single  individual  more 
varied  and  complex  modifications  than  are  produced  in 
thousands  of  generations  of  the  species  by  the  slow  and 
wasteful  process  of  natural  selection. 

The  function  of  consciousness  may  be  compared  to  that 
of  a  complex  machine  like  a  printing  press  or  the  harvester, 
which  does  with  infinitely  greater  speed  and  ease  that  which 
was  formerly  done  slowly  and  laboriously  with  very  simple 
tools. 

Note.  —  For  convenience  and  clearness  consciousness  is  treated 
as  if  it  were  an  entity  added  to  and  presiding  over  the  ner\'ous  mech- 
anism. The  author,  however,  does  not  wish  to  assert  or  imply  any 
philosophy  or  theory  in  regard  to  the  relation  of  mind  and  matter. 
He  wishes  merely  to  describe  the  phenomenon  so  that  others  shall 
know  to  what  he  refers.  Whether  consciousness  is  a  distinct  entity 
or  only  a  phenomenon  that  appears  as  a  result  of  a  certain  kind  of 
nervous  functioning  is  not  the  most  important  question  from  the 
purely  psychological  standpoint.  The  important  fact  to  be  noted 
is  that  where  there  is  a  certain  type  of  nervous  functioning  there  is 
usually  consciousness  and  a  different  and  more  effective  form  of 
activity.  This  new  type  of  functioning  implied  by  the  word  con- 
sciousness must  be  an  important  factor  in  the  evolution  of  creatures 
showing  it,  otherwise  it  would  not  have  been  developed  to  the  re- 


CONSCIOUSNESS  191 

markable  extent  that  it  has  in  man.  The  important  thing  for  the 
psychologist  to  find  out  is  not  what  it  is  but  what  it  does  and  how  it 
docs  it,  making  all  use  that  he  can  of  both  subjective  and  objective 
facts. 

ORGANIC    UNITY   AND   CONTINUITY 

The  physiological  activity  of  all  organisms  is  unifying  to 
a  greater  or  less  degree.  In  the  case  of  the  lower  animals, 
such  as  worms,  insects,  and  the  lower  vertebrates,  the  unity 
is  comparatively  slight,  especially  as  regards  the  immedi- 
ate activities.  An  animal  may  be  divided  symmetrically 
into  two  parts,  each  of  which  will  perform  its  special  func- 
tions nearly  as  well  as  before.  In  some  creatures,  as  for 
instance  the  angleworm,  each  part  produces  new  segments 
and  becomes  a  complete  individual. 

In  the  case  of  a  very  small  organism  with  no  specialized 
sense  organs  it  is  quite  reasonable  to  suppose  that  the  mere 
fact  of  lack  of  physical  and  physiological  equilibrium  leads 
to  movements  that  produce  more  favorable  results.  In  the 
case  of  larger  animals  with  more  specialized  sense  and 
motor  organs  but  with  only  a  few  unvarying  forms  of 
reaction  it  is  also  conceivable  that  the  behavior  may  be 
without  consciousness. 

In  the  case  of  human  beings  the  physiological  processes 
of  respiration,  digestion,  etc.,  are  unified  very  completely. 
A  change  in  the  functioning  of  one  organ  is  always  fol- 
lowed by  correlative  changes  in  other  organs.  In  the  case 
of  sudden  changes  in  air  or  food  or  when  there  is  imperfect 
working  of  the  vital  organs,  we  are  conscious  that  something 
is  wrong,  but  ordinarily  consciousness  exercises  no  direct 
control  over  the  correlated  and  unified  activities  of  the 
vital  organs.     This  is  true  not  only  under  constant  condi- 


192  GENETIC   PSYCHOLOGY 

tions  but  when  organisms  are  being  adapted  to  changes 
in  the  environment  and  when  all  portions  of  the  body  are 
growing  and  developing.  A  change  in  rate  of  breathing 
is  met  by  change  in  rate  of  heart  beat,  blood  pressure,  etc. 
The  unconscious  unification  and  adjustment  of  activities, 
by  which  the  temperature  is  kept  almost  constant  as  we 
pass  from  a  furnace-heated  room  to  the  zero  air  outside, 
are  far  more  complex  than  any  heating  apparatus  by  means 
of  which  the  temperature  of  a  house  is  regulated. 

Again,  purely  physiological  activities  are  correlated  not 
only  with  other  activities  taking  place  at  the  same  time,  but 
with  activities  that  have  taken  place  in  the  past  or  are  to 
take  place  in  the  future.  This  is  shown  in  the  growth  of 
all  organisms,  both  plant  and  animal.  Each  stage  of  de- 
velopment is  preparatory  to  the  one  that  is  to  follow,  and  a 
failure  in  any  portion  or  stage  of  the  growth  affects  other 
parts  in  other  stages  of  development.  This  is  true  even 
in  the  case  of  animals  in  which  there  is  a  distinct  break 
in  the  stages  of  development,  the  adult  frog  or  insect  vary- 
ing greatly  according  to  the  temperature  and  food  condi- 
tions to  which  the  tadpole  or  larva,  from  which  it  devel- 
oped, was  subjected. 

We  usually  think  of  physiological  activities  in  animals  as 
being  continuous,  but  in  them  as  well  as  in  plants  there  may 
be  complete  suspension  of  activity  for  a  considerable  time 
without  death.  This  is  especially  true  of  the  lower  animals. 
The  caterpillar  may  be  frozen  solid,  and  when  thawed  out 
be  as  active  as  ever.  Frogs  and  snakes  can  also  remain 
inactive  because  of  cold,  for  long  periods,  without  destruc- 
tion to  their  lives.  In  the  higher  animals  and  in  man  com- 
plete suspension  for  a  short  time  of  the  vital  functions,  as 


CONSCIOUSNESS  193 

in  drowning,  may  occur,  with  subsequent  reanimation. 
In  general,  however,  the  chief  physiological  processes  are 
continuous,  although  in  sleep  some  of  the  nervous  processes 
apparently  cease. 

SEEMING    CONTINUITY   OF    CONSCIOUSNESS 

In  our  own  experience  we  know  that  there  is  a  paral- 
lel series  of  conscious  or  subjective  experiences  corre- 
sponding to  the  physiological  and  objective  movements 
that  we  are  making.  It  seems  to  us  as  if  the  subjective 
phenomena  formed  a  continuous  series.  There  must  be 
large  gaps  during  sleep,  but  our  conscious  states  seem  to 
begin  where  they  left  off.  In  cases  of  injury  to  the  brain, 
consciousness  has,  in  individual  cases,  returned  after  weeks 
or  months  without  the  individual  being  aware  of  any 
break  in  his  conscious  life  until  he  has  been  informed  of 
events  that  have  occurred  in  the  meantime.  Notwithstand- 
ing that  there  really  are  breaks  in  consciousness  it  always 
seems  to  us  to  be  unified  and  continuous.  Whether  this 
is  true  of  consciousness  other  than  human  we  cannot  say. 
It  is  conceivable  and  quite  probable  that  consciousness  in 
the  lower  animals  may  have  many  more  and  much  longer 
breaks  or  blanks  than  in  the  case  of  human  beings.  It 
may  be  that  their  subjective  life  consists  in  only  occasional 
flashes  of  consciousness  preceded  and  followed  by  long 
intervals  that  are  blank.  When  complex  activities  are 
performed  and  unified,  consciousness  may  be  present  and 
help  produce  such  unification,  and  then  as  soon  as  some 
of  the  varied  stimuli  have  ceased,  it  may  disappear. 

It  may  very  well  be  questioned  whether  even  the  higher 


194  GENETIC   PSYCHOLOGY 

birds  and  mammals  have  a  continuous  consciousness 
like  that  of  man.  To  have  a  continuous  consciousness  it 
would  seem  as  if  there  must  be  not  only  many  and  varied 
sensations,  but  memories  of  past  experiences  as  a  constant 
part  of  the  content  of  consciousness.  When  we  look  into  our 
own  consciousness  we  rarely  find  it  occupied  with  sensations 
only.  They  usually  form  only  a  small  part  of  its  content. 
If  all  images  and  ideas  were  dropped  out  of  consciousness 
we  should  have,  if  conscious  at  all,  a  very  different  con- 
sciousness from  what  we  now  have  most  of  the  time.  A 
dog  or  a  cat  resting  quietly  is  having  but  few  changes  in 
sensory  stimulation,  and  if  he  has  no  free  images  of  past 
and  possible  future  experiences,  the  contents  of  his  con- 
sciousness, if  any,  must  be  very  meager,  perhaps  more  so 
than  our  own  when  we  are  falling  into  a  comfortable  sleep ; 
for  then  our  consciousness  is  occupied  with  images  rather 
than  sensations.  When  we  awake,  although  our  con- 
sciousness seems  to  begin  where  it  left  off,  yet,  since  we 
possess  free  ideas,  we  can  be  convinced  that  events  have 
taken  place  without  our  being  aware  of  them. 

It  would  seem  to  be  impossible  for  a  creature  without 
memory  in  some  form  to  possess  a  continuous  conscious- 
ness and  be  av.-are  of  its  own  subjective  life  as  continuous. 
Where  the  memory  is  merely  a  reproduction  of  a  series 
of  experiences  in  the  same  order  in  which  they  occurred, 
the  consciousness  must  be  quite  different  from  that  of 
man.  This  is  perhaps  illustrated  by  the  incident  of  Dar- 
win's dogs.  They  were  in  the  habit  of  meeting  him  some 
distance  from  the  house  and  playing  around  him  as  he 
walked  up  the  path.  After  an  absence  of  several  years 
their  behavior  when  he  came  was  exactly  the  same.     This 


CONSCIOUSNESS  195 

shows  remarkable  memory  in  the  sense  of  retaining 
modifications  of  behavior  after  a  long  interval.  But 
evidently  the  consciousness  must  be  quite  different  from 
that  of  man.  It  is  safe  to  say  that  no  human  friend  of 
Darwin's  met  him  after  years  of  absence  and  treated  him 
in  exactly  the  same  way  as  when  they  were  meeting  every 
day.  In  the  case  of  man  an  acquired  mode  of  behavior 
is  not  only  retained  but  in  his  memory  the  present  situation 
is  contrasted  with  that  which  accompanied  the  act  being 
reproduced. 

The  possession  of  a  continuous  consciousness  such  as 
man's  would  scarcely  be  possible  without  the  ability  to 
form  free  ideas  and  represent  not  only  past  experiences 
but  one's  mental  states  and  the  surroundings  in  which  they 
occurred.  Speaking  figuratively,  the  physiological  ac- 
tivities furnish  the  canvas,  the  reflex  and  habitual  activi- 
ties the  background,  and  present  situations  the  moving 
pictures  in  the  panorama  of  consciousness.  All  of  this 
may  be  represented  in  the  consciousness  of  a  dog,  but  when 
he  is  passive  and  has  little  variation  in  external  stimulation, 
the  whole  scene  may  almost  disappear.  In  man's  con- 
sciousness there  is  present  all  that  there  is  in  the  dog's, 
and  in  addition  free  images  and  ideas  that  are  appearing 
and  being  combined  in  all  sorts  of  ways  to  represent  past 
and  possible  future  pictures  that  are  contrasted  with  those 
of  the  present.  When  an  animal  has  new  experiences, 
the  panorama  presented  to  his  consciousness  changes ;  but 
probably  there  is  no  consciousness  of  the  former  state  that 
has  been  changed,  no  distinguishing  between  present  stimu- 
lations and  a  reproduction  of  a  series  of  past  stimula- 
tions in  the  form  of  anticipatory  images.     The  dog  which 


196  GENETIC   PSYCHOLOGY 

chased  a  squirrel  up  a  tree  and  barked  at  it  was  modified 
by  the  experience  so  that  the  next  time  he  passed  that  way 
he  ran  to  the  tree  and  barked  as  before.  Not  having  free 
ideas  he  had  not  analyzed  the  situation  and  could  not 
represent  the  elements  of  the  former  experience  so  as  to 
distinguish  and  contrast  the  present  experience  with  the 
former  one.  His  mental  state  was  probably  similar  to 
that  of  the  normal  school  teacher  who,  when  the  hymn  was 
announced  at  chapel  exercises,  opened  the  book  of  scrip- 
tural selections  at  the  page  named.  In  general,  the  per- 
ceptual recognitions  or  so-called  "memories"  of  animals 
are  in  consciousness  probably  very  similar  to  habitual  and 
semi-mechanical  acts  in  human  beings. 

In  the  case  of  man,  experiences  not  only  modify  behavior 
and  the  pictures  presented  to  consciousness  but  those 
experiences  may  be  reproduced,  distinguished  from,  and 
contrasted  with,  present  experiences.  He  is  thus  able  to 
recognize  changes  in  his  mental  pictures  and  to  fill  in, 
from  the  reports  of  others,  pictures  of  events  that  have 
taken  place  while  he  was  unconscious.  He  can  also  look 
back  upon  his  consciousness  as  it  was,  under  certain  con- 
ditions, and  discern  in  what  respect  it  differs  from  what  it 
is  now.  It  is  important  therefore  to  a  continuous  sub- 
jective life  that  one  shall  be  able  not  only  to  reproduce 
former  experiences,  but  that  he  shall  also  be  able  to  repro- 
duce the  background  against  which  they  appeared  and  be 
able  to  shift  images  freely  from  one  background  to  another. 

The  physiological  functioning  that  provides  the  con- 
scious background  of  subjective  life  is  of  great  significance 
in  the  individual  consciousness.  This  is  clearly  shown  in 
alterations  of  behavior  and   in  conscious  mental   states 


CONSCIOUSNESS  197 

when  health  is  seriously  impaired  or  when  there  are  im- 
portant changes  in  physiological  processes,  such  as  may 
be  produced,  for  instance,  by  taking  food  and  rest  when 
extremely  hungry  and  tired.  The  comparatively  perma- 
nent groundwork  of  our  subjective  life  is  often  thus  so 
completely  changed  within  a  short  time  that  we  seem  to 
be  looking  upon  a  different  world.  In  pathological  cases, 
where  physiological  disturbances  involve  loss  of  sen- 
sory and  motor  powers,  a  patient  frequently  shows  com- 
plete and  perhaps  permanent  change  of  personality. 
Sometimes  he  is  conscious  of  the  change  and  because  of 
his  loss  of  sensitivity  he  may  have  the  idea  that  he  has  lost 
his  personal  identity,  that  he  is  dead,  or  that  his  body  has 
been  transformed  into  some  inanimate  thing.  Sudden 
changes  in  instinctive  and  habitual  acts  may  also  result 
in  important  changes  in  consciousness.  The  individual 
appears  to  himself  and  to  those  who  know  him  to  be  en- 
tirely transformed  in  character  either  for  the  better  or  the 
worse.  The  ideas  that  were  associated  with  the  former 
physiological  and  habitual  reactions  are  either  replaced 
by  or  contrasted  with  those  associated  with  the  present 
mode  of  life.  When  the  old  ideas  persist  there  is  not  a 
complete  transformation  in  character  although  there  is  in 
bodily  condition  and  outward  behavior.  Frequently, 
however,  the  ideas  correspond  to  the  situation  and  the 
behavior.  For  example,  he  who  assumes  the  clothes  and 
behavior  of  a  beggar  is  likely  to  take  on  his  consciousness. 
It  is  for  this  reason  that  men  are  often  scarcely  recognizable 
after  they  have  engaged  in  a  new  occupation  or  sometimes 
when  seen  on  a  vacation.  Sudden  changes  in  physiologi- 
cal, instinctive,  and  habitual  acts  may  therefore  produce 


198  GENETIC    PSYCHOLOGY 

greater  breaks  in  the  seeming  continuity  of  consciousness 
than  complete  blanks  in  the  conscious  life. 

OBJECTIVE   AND   SUBJECTIVE   TERMS 

The  purely  objective  study  of  reactions  is  well  illustrated 
by  experiments  of  Paplow  and  Nicoli  to  discover  the  effects 
of  various  stimuli  upon  glandular  action  in  a  dog.  A  means 
was  devised  by  which  the  amount  and  rate  of  flow  of  saliva 
could  be  measured.  It  was  found  that  under  certain 
definite  conditions  each  stimulus  produced  a  specific 
reaction,  which  was  modified  by  repeated  association  and 
repetition.  After  a  certain  odor,  color,  or  sound  had  been 
presented  to  the  dog  just  before  feeding,  a  number  of 
times,  there  resulted  an  increased  flow  of  saliva  whenever 
that  stimulus  was  given,  while  no  such  response  was  made 
to  other  stimuli,  though  only  slightly  different.  In  reac- 
tion to  sound  stimulations  the  glands  seemed  to  be  more 
discriminating  than  the  consciousness  of  man,  a  tone  only 
one  fourth  of  a  tone  abo\'e  or  below  that  associated  with 
feeding  not  being  reacted  to  by  increased  flow  of  saliva 
as  was  the  exact  tone  associated  with  being  fed. 

In  our  own  experience  there  may  be  an  activity  produced 
by  a  repeated  stimulus,  that  we  call  a  perception,  without 
stopping  to  inquire  as  to  just  what  nervous,  muscular,  or 
glandular  reactions  have  been  made.  With  complete 
knowledge  of  the  subject  one  might  specify  in  detail  all 
the  physiological  and  psychical  changes  produced  by  the 
stimulus  but  such  accuracy  of  expression  would  be  a 
painfully  cumbersome  mode  of  describing  behavior.  With 
our  present  knowledge  it  is  convenient  to  indicate  by  some 


CONSCIOUSNESS  1 99 

subjective  term,  as  "  sensation,"  "  perception,"  or  "  image, " 
the  reaction  that  takes  place  without  specifying  its  elements. 
This  may  even  be  done  when  one  docs  not  know  posi- 
tively that  any  change  in  consciousness  has  been  produced, 
though  not  unless  such  reactions  are  supposed  to  have  in- 
volved consciousness  at  some  time. 

Since  the  behavior  of  animals  is  so  largely  under  the 
influence  of  immediate  surroundings,  it  is  possible  to  use 
objective  terms  alone  in  describing  it,  though  it  is  rather 
awkward  to  so  confine  one's  self.  To  speak  accurately 
in  objective  terms,  instead  of  saying  that  an  animal  dis- 
criminates sensations  of  red  from  sensations  of  violet, 
we  should  say  that  he  reacts  differently  to  vibrations  of 
light  of  the  vibration  rate  of  435  billion  per  second  from 
those  of  the  vibration  rate  of  769  billion.  When  sub- 
jective terms  are  used  in  describing  animal  behavior  it 
should  always  be  understood  that  they  do  not  imply  the 
same  conscious  states  as  we  have,  but  merely  that  the 
stimuli  producing  different  conscious  states  in  us  produce 
different  reactions  and  probably  correspondingly  different 
conscious  states  in  animals.  It  is  not  at  all  likely  that 
the  color  sensations,  for  example,  are  just  the  same  in 
even  the  highest  animals  as  they  are  in  ourselves. 

In  describing  the  behavior  of  man  it  is  not  only  con- 
venient but  absolutely  necessary  to  use  subjective  terms. 
A  large  part  of  the  mental  activity  of  man  is  independent 
of  external  stimulation  and  its  real  nature  is  not  mani- 
fested by  outward  movement.  Careful  experiments  show 
that  mental  activity  is  associated  with  changes  in  nervous, 
muscular,  and  glandular  processes,  but  in  many  instances 
these  objective  reactions   are  known  only   by  inference 


200  GENETIC   PSYCHOLOGY 

from  other  cases  of  a  similar  character,  in  which  a  direct 
correlation  has  been  found.  Even  when  describing  ner- 
vous processes  it  is  often  convenient  to  use  subjective 
terms  which  are  generally  recognized  as  being  correlated 
with  those  processes.  On  the  other  hand,  it  is  sometimes 
convenient  to  express  the  activities  of  consciousness  in 
physiological  terms,  as  when  we  speak  of  association  of 
ideas  in  terms  of  connections  between  brain  centers. 

Although  inaccurate  there  is  considerable  justification  for 
the  use  of  words  in  these  ways.  This  is  found  in  the  fact 
that  almost  the  same  nervous  process  may  take  place  at 
one  time  with  consciousness  and  at  another  time  without. 
As  we  have  already  seen,  consciousness  is  most  prominent 
in  new  adjustments  of  behavior  and  least  prominent  or 
entirely  absent  in  reflex,  instinctive,  and  habitual  adjust- 
ments. It  is  therefore  doubtless  true  that  a  great  many 
nervous  processes  which  at  one  time  in  the  life  of  the  indi- 
vidual were  represented  in  consciousness  may  at  another 
time  proceed  almost,  if  not  wholly,  w' ithout  such  representa- 
tion. In  such  cases  it  is  convenient  to  use  the  subjective 
term  implying  consciousness,  but  it  is  well  to  have  it 
understood  that  the  process  may  take  place  without  any 
such  representation  in  consciousness  as  may  at  one  time 
have  occurred  and  as  the  words  now  imply.  When  we 
are  learning  new  movements  we  are  conscious  of  many 
sensations  and  images  of  which,  at  a  later  stage,  we  are 
not  at  all  conscious.  The  same  is  true  of  perceptions. 
Relatively  unfamiliar  perceptions  involve  images  to  a  far 
greater  extent  than  when  they  become  habitual,  e.g.  a 
voice  not  often  heard  may  call  up  several  images  before  we 
recognize  to  whom  it  belongs,  while  a  familiar  voice  is 


CONSCIOUSNESS  20I 

recognized  at  once  without  any  preliminary  images.  The 
question  as  to  whether  images  are  used  in  perceptions  of 
any  given  kind  should  be  regarded  largely  as  a  genetic 
problem  rather  than  as  a  problem  of  fixed  modes  of  mental 
procedure,  for  the  imagery  connected  with  any  perception 
may  vary  indefinitely  with  needs,  interests,  and  practice. 
For  example,  the  sound  of  approaching  footsteps  may 
excite  many  and  definite  images  in  some  and  no  appre- 
ciable images  of  any  kind  in  others  according  to  different 
interests,  needs,  and  degree  of  familiarity.  The  images 
involved  in  most  perceptions  are  usually  not  free  images, 
but,  as  already  suggested,  anticipatory  and  of  the  nature 
of  secondary  or  mediated  sensations. 

Not  only  do  processes  that  are  at  first  conscious  become, 
with  repetition,  unconscious  under  ordinary  circumstances, 
though  they  may  usually  at  will  be  performed  consciously, 
but  the  opposite  condition  is  found,  of  processes  which  were 
originally  performed  without  consciousness  that  may  also 
be  performed  with  consciousness.  This  is  true  of  nearly 
all  the  physiological  processes.  We  breathe  either  con- 
sciously or  unconsciously  and  within  certain  limits  we  can 
control  the  rate  of  breathing  as  we  choose.  A  few  indi- 
viduals have  acquired  control  over  the  movements  of  the 
heart  so  that  they  can  increase  or  decrease  its  rate  of  move- 
ment and  can  stop  or  start  it  at  pleasure.  Glands  such  as 
the  tear  glands  are  in  some  persons  under  the  control  of 
consciousness.  Consciousness  can  also  acquire  control 
over  muscles  that  are  ordinarily  classed  as  non-voluntary, 
e.g.  the  muscles  of  the  ear.  The  circulation  of  the  blood 
in  any  part  of  the  body  may  also  be  increased  by  conscious 
attention  to  that  portion  of  the  body,  and  the  representation 


202  GENETIC    PSYCHOLOGY 

of  a  burn  has  been  known  in  some  instances  to  produce 
physiological  effects  similar  to  that  produced  by  a  hot 
iron.  The  distinction  between  voluntary  and  non-volun- 
tary action  and  between  mere  conscious  accompaniment 
and  conscious  direction  of  activities,  cannot  be  closely 
drawn.  Neither  are  the  possibilities  of  acquisition  of 
voluntary  control  well  known.  If  an  individual  gave  as 
much  attention  to  acquiring  conscious  control  of  the 
physiological  processes  as  he  gives  to  acquiring  control 
of  the  muscles  of  his  hand  it  may  be  that  he  could  gain 
almost  as  much  control  over  the  processes  of  circulation, 
digestion,  repair,  and  growth  as  he  now  has  over  his 
fingers  or  his  vocal  organs. 

Again,  as  we  analyze  wholes  into  their  elements  and  form 
new  combinations  we  become  conscious  of  an  infinite 
number  of  things  of  which  under  the  same  external  cir- 
cumstances we  were  not  previously  conscious.  All  mental 
development  involves  the  continual  emergence  of  new 
states  of  consciousness,  just  as  the  formation  of  habits 
involves  their  disappearance.  The  result  is  that  as  long 
as  we  are  developing  we  are  increasing  the  number  and 
variety  of  actual  and  possible  conscious  states,  though 
continually  becoming  less  conscious  of  activities  often 
repeated. 

The  tendency  on  the  part  of  physiologists  is  to  emphasize 
the  importance  of  nervous  processes  and  to  seek  to  find  a 
complete  explanation  of  all  behavior  in  the  laws  of  physio- 
logical activity.  The  tendency  on  the  part  of  the  psy- 
chologist, on  the  other  hand,  is  to  seek  to  explain  what 
takes  place  in  subjective  terms  and  as  the  result  of  psy- 
chological laws.     From  neither  point  of  view  is  it  possible 


CONSCIOUSNESS  203 

to  gain  a  complete  idea  of  all  that  is  taking  place.  A  large 
proportion  of  the  activity  of  the  nervous  centers  is  not  ac- 
companied by  consciousness  and  hence  the  psychological 
account  is  quite  inadequate.  On  the  other  hand,  it  is 
possible  to  determine  to  only  a  slight  extent  what  is  taking 
place  in  the  nervous  centers,  except  so  far  as  it  is  repre- 
sented in  consciousness  and  in  so  far  as  changes  in  nerve 
centers  produce  changes  in  external  movements  or  condi- 
tions. Neither  the  physiologist  nor  the  psychologist  should 
push  his  explanations  too  far  into  the  field  that  is  open  only 
from  the  other  point  of  view.  Both,  however,  should  feel 
at  liberty  to  use  the  terms  that  best  serve  their  purpose  in 
describing  and  explaining,  providing  it  is  understood  or 
made  clear  by  the  context,  that  a  certain  type  of  activity 
which  may  be  conceived  either  as  a  physiological  or  as  a 
conscious  process,  is  taking  place,  without  implying  that 
consciousness  either  is  or  is  not  present  in  the  particular 
instance  described. 

Words  must  be  used  in  this  somewhat  loose  way  in 
describing  the  behavior  of  men  and  animals  or  else  a  new 
set  of  terms  must  be  invented.  Attempts  have  been  made 
to  invent  terms  that  are  wholly  objective,  but  this  is  open 
to  the  same  objection  as  is  the  use  of  strictly  psychologi- 
cal terms  to  describe  conscious  states.  If  we  had  both 
objective  and  subjective  terms  we  would  still  be  at  a  loss 
to  describe  processes  that  may  or  may  not  be  accompanied 
by  consciousness,  and  processes  that  at  one  time  may  be 
accompanied  by  consciousness  and  at  another  time  per- 
formed without  it  either  in  the  same  or  in  different  creatures. 
Terms  indicating  the  process  meant,  but  not  necessarily 
implying  that  it  is  with  or  is  without  consciousness,  are 


204  GENETIC   PSYCHOLOGY 

necessary  until  we  know  more  regarding  what  kinds  of 
processes  may  be  performed  witliout  consciousness  and 
what  kinds  must  be  so  accompanied,  and  in  what  stages  of 
development  and  under  just  what  circumstances  must 
consciousness  continue  to  be  present  in  order  that  the 
process  may  be  performed. 

The  term  "subconsciousness"  has  come  into  extensive 
use  recently,  but  has  probably  added  to,  rather  than  de- 
creased, the  difficulties  of  the  situation.  It  is  used  to  de- 
scribe processes  that  take  place  outside  of  the  ordinary 
consciousness,  and  usually  implies  that  a  consciousness  in 
some  way  distinct  from  the  primary,  normal  consciousness 
of  an  individual  is  directing  some  of  his  activities.  This 
supposition  is  easily  made  and  difficult  to  disprove.  It 
would  be  safer  to  use  subjective  terms  when  convenient  in 
describing  what  a  hypnotic  subject  does,  without  neces- 
sarily implying  that  there  is  any  consciousness  accompany- 
ing the  process.  It  is  better  to  do  this  and  then  investi- 
gate more  fully  as  to  what  kinds  of  acts  may  be  performed 
without  consciousness.  It  may  be  found  that  all  the  cases 
of  subconsciousness,  or  supposed  cases  of  a  consciousness 
separate  from  the  ordinary  consciousness,  are  really  cases 
of  acts  that  may  be  performed  without  conscious  direction 
or  that  they  are  supervised  by  an  alternating  consciousness. 
This  may  well  be  illustrated  by  a  case  reported  by  Dr.  Prince 
of  an  individual  who  was  able  to  perform  complex  processes 
of  which  his  ordinary  consciousness  seemed  to  know  noth- 
ing. Dr.  Prince  asked  the  subject,  when  in  a  state  desig- 
nated as  "consciousness  B,"  to  work  a  problem  in  the  com- 
putation of  time,  whenever  the  figures  indicating  the  hours 
should  be  presented.     The  ordinary  consciousness  known 


CONSCIOUSNESS  205 

as  "A"  was  then  given  the  task  of  writing  a  poem  on  a 
sheet  of  paper  that  had  in  the  margin  the  figures  to  be  used 
as  data  by  consciousness  B.  So  far  as  could  be  determined, 
consciousness  A  took  no  notice  of  these  numbers,  but  as 
soon  as  consciousness  B  was  evoked  by  hypnotism,  the 
solution  of  the  problem  was  given.  Dr.  Prince  sui)posed 
that  there  really  must  have  been  a  consciousness  B  direct- 
ing the  solution  of  this  problem  while  consciousness  A 
was  engrossed  with  the  writing  of  the  poem.  It  is  pos- 
sible, however,  and  equally  reasonable  to  suppose,  that  the 
brain  was  consciously  adjusted  to  perform  the  problem 
at  the  time  of  receiving  directions  to  do  so  whenever  the 
figures  were  presented,  and  that  the  actual  working  of  the 
problem  was  done  automatically  while  the  only  conscious- 
ness present,  viz.,  the  normal  consciousness,  was  occupied 
with  the  poem,  in  much  the  same  way  as  a  person  may 
adjust  himself  to  reading  aloud  and  then  read  a  whole  page 
while  intently  thinking  of  something  else. 

In  general,  the  function  of  consciousness  is  not  to  actually 
do  things  but  to  adjust  apparatus  for  doing  them,  note  the 
results,  and  readjust  as  needed.  It  is  not  wise  therefore 
to  assume  that  what  is  done  without  the  knowledge  of 
the  ordinary  consciousness  must  have  been  directed  by 
another  consciousness.  The  term  "subconscious"  often 
implies  this.  Such  use  of  the  word  opens  the  way  for  all 
kinds  of  suppositions  regarding  the  action  of  one  or  more 
separate  consciousnesses,  a  reliable  knowledge  of  which 
is,  in  the  nature  of  the  case,  unattainable.  The  word  has 
therefore  been  more  of  a  stimulus  to  the  imagination  than 
a  contribution  to  accurate  thinking,  and  should  be  used 
with  caution  if  at  all. 


2o6  GENETIC   PSYCHOLOGY 

PROBABLE    GENERAL    CHARACTERISTICS    OF   THE    CON- 
SCIOUSNESS   OF   ANIMALS 

No  progress  can  be  made  in  understanding  the  minds 
of  animals  by  supposing  that  they  have  a  consciousness 
entirely  different  from  our  own;  and  we  are  led  into  error 
if  we  suppose  their  consciousness  to  be  exactly  like  ours, 
especially  in  its  more  highly  developed  phases.  We  can 
only  hope  to  attain  some  knowledge  of  the  truth  by  study- 
ing carefully  the  variations  in  our  own  consciousness  and 
inferring  from  all  known  facts  the  nature  and  extent  of 
such  variations  in  the  consciousness  of  animals,  giving 
special  attention  to  the  least  distinct  and  highly  developed 
of  our  own  conscious  states. 

We  have  already  found  that  the  fundamental  function 
of  consciousness  is  to  unify  experiences,  and  that  to  itself, 
human  consciousness  is  always  unified  and  continuous, 
although  there  are  actual  breaks  in  the  conscious  life  dur- 
ing sleep.  In  recalling  the  events  of  the  day  or  the  week 
the  larger  number  are  not  recalled,  yet  the  omissions  give 
no  sense  of  the  lack  of  continuity.  This  may  or  may  not 
be  true  of  the  consciousness  of  animals.  The  breaks  in 
their  consciousness  maybe  much  longer  and  more  frequent, 
but  to  the  consciousness  of  an  animal  there  may  be  con- 
tinuity and  unity  but  probably  a  continuity  not  involving  a 
past  and  a  future  related  to  the  present,  —  a  mere  negative 
continuity  in  which  no  break  is  felt,  because  only  the  pres- 
ent is  cognized. 

Observing  our  own  consciousness  at  different  times  and 
comparing  the  consciousness  of  persons  of  varying  age 
and  culture,  we  find  that  there  are  immense  differences 


CONSCIOUSNESS  207 

in  the  content  of  consciousness.  In  some  instances  it  is 
crowded  with  sensations,  images,  and  ideas,  each  carrying 
with  it  a  host  of  other  images  and  ideas  as  a  background, 
while  in  other  cases  consciousness  is  comparatively  bare 
of  content.  In  the  case  of  animals  with  few  sense  organs 
and  little  change  in  external  surroundings  and  no  power 
of  representation,  consciousness,  if  present,  must  be  of  a 
simpler  character  than  any  that  we  have  ever  experienced. 
It  is  probable  that  the  content  of  consciousness  of  even  the 
higher  animals  at  their  best  is  far  more  meager  than  that 
of  human  beings  at  their  lowest. 

It  is  a  well-known  fact  that  the  span  of  consciousness 
increases  greatly  with  age,  experience,  and  familiarity 
with  the  experience  being  held  in  mind.  Where  a  child 
can  think  of  two  objects,  numbers,  or  words  so  as  to  name 
or  repeat  them,  an  adult  would  readily  name  or  repeat 
three  or  four  times  as  many.  In  observing  trains  of  as- 
sociation the  same  fact  may  be  noticed.  The  child's 
trains  of  thought  are  very  short  and  usually  initiated  by 
external  stimulation,  while  the  adult's  trains  of  thought  are 
frequently  very  long  and  almost  independent  of  external 
stimulation.  The  content  of  an  adult's  consciousness  is  still 
further  increased  by  arrangement  into  groups  and  scries 
without  trying  to  focalize  individual  elements.  From 
the  actions  of  animals  it  is  fair  to  infer  that  their  span  of 
consciousness  and  their  trains  of  thought  are  very  brief 
compared  with  those  of  even  a  two-year-old  child.  In 
fact,  most  of  their  behavior  and  probably  their  conscious 
states  are  the  result  of  immediate  sensory  stimulation. 

We  know  that  our  own  consciousness  may  be  of  a  higher 
or  lower  degree  of  intensity  and  more  or  less  dear  and 


2o8  GENETIC    PSYCHOLOGY 

discriminating.  Clearness  in  the  form  of  accurate  discrim- 
ination, and  intensity  in  the  form  of  feeling,  do  not  neces- 
sarily occur  together,  but  frequently,  if  not  usually,  is  the 
reverse  true.  The  fact  that  the  behavior  of  animals  is 
much  less  modified  by  severe  injuries  than  in  the  case  of 
man  would  suggest  the  probability  that  the  intensity  of 
conscious  feeling  is  in  them  very  much  less  than  it  is  in 
man.  On  the  other  hand,  the  wonderful  accuracy  of  dis- 
crimination in  special  lines,  notably  in  that  of  smell, 
indicates  that  in  some  cases  at  least  animals  do  not  lack 
in  clearness  of  consciousness.  This  may  not,  however, 
indicate  a  generally  highly  illuminated  consciousness. 
Just  as  a  light  is  much  more  easily  and  clearly  discrimi- 
nated in  darkness  than  in  the  broad  light  of  the  noon- 
day sun,  so  some  stimulations  may  stand  out  with  great 
clearness  in  a  consciousness  otherwise  comparatively  dim. 
It  is  worthy  of  note  also  that  our  finest  tactual,  visual,  and 
auditory  discriminations  are  not  of  stimuli  that  produce 
pain  or  pleasure,  but  rather  of  those  that  do  not,  though 
they  may  be  suggestive  of  painful  or  pleasurable  stimuli 
to  follow. 

Perhaps  the  most  common  and  marked  variation  in 
human  consciousness  is  in  the  unevenness  of  its  content, 
or,  in  other  words,  in  its  characteristic  of  being  focalized 
upon  a  portion  of  its  contents  while  other  portions  are  but 
dimly  felt.  Not  only  is  this  focus  being  changed  from 
one  element  to  another,  but  the  degree  of  focalization  or 
of  concentration  of  attention  varies  immensely  in  different 
minds  and  in  the  same  mind  at  different  times.  In  idle 
moments  of  day  dreaming  there  may  be  almost  if  not  entire 
lack  of  focalization.     In  cases  of  fatigue  also  it  often  be- 


CONSCIOUSNESS  209 

comes  impossn)le  to  keep  the  attention  fixed  upon  the 
subject  in  hand.  Diffusion  of  attention  is  usually  more 
marked  in  children  than  in  adults,  although  the  difference 
is  perhaps  not  as  great  as  is  usually  suj)posed.  The  child's 
attention  changes  much  more  frequently  than  an  adult's 
and  he  has  less  power  to  direct  it  in  any  required  way; 
but  in  some  instances,  at  any  rate,  there  is  every  evidence 
of  very  complete  momentary  concentration  of  attention 
upon  one  thing  on  the  part  of  even  very  young  children. 
What  is  true  of  children  is  true  of  animals  in  a  greater 
degree.  We  cannot  therefore  say  positively  that  their 
consciousness  is  lacking  in  focalization,  but  it  may  be  in 
power  of  sustaining  it.  The  difference  perhaps  between 
human  and  animal  focalization  is  in  the  extent  and  variety 
of  the  content  involved.  It  may  very  well  be  that  when 
the  consciousness  of  an  animal  is  focalized  there  is  little 
or  no  other  content  besides  that  which  is  focalized. 

Thus  far  our  discussion  has  been  concerned  chiefly  with 
the  content  of  consciousness,  and  it  is  of  this  that  we  know 
most.  Of  consciousness  as  such,  apart  from  its  content, 
we  know  little  or  nothing.  It  is  difficult  to  describe  the 
difference  between  consciousness  when  it  has  much 
content  and  when  it  is  comparatively  empty.  Some 
persons  maintain  that  they  are  at  times  conscious  but  not 
conscious  of  any  definite  thing.  A  few  claim  to  be  able  at 
will  to  em])ty  their  consciousness  of  all  content.  To  most 
persons  this  condition  is  almost  if  not  quite  inconceivable. 
Since,  however,  creditable  observers  claim  that  this  is 
true  of  themselves  we  are  not  justified  in  arbitrarily  deny- 
ing its  possibility.  It  is  probable,  however,  that  this  seem- 
ing absence  of  content  is  merely  an  extreme  case  of  dilTu- 
p 

OF  —-iC. 
Of 


2IO  GENETIC    PSYCHOLOGY 

sion  of  attention  under  conditions  in  which  there  is  little 
variety  in  kind  and  degree  of  stimulation.  If  so,  then  the 
seeming  bareness  of  consciousness  is  due  to  the  fact  that 
there  is  no  focalization  upon  any  one  part.  Whether 
animals  have  this  kind  of  conscious  state  frequently  we 
cannot  say,  but  it  is  not  improbable  that  in  many  instances 
such  states  alternate  in  the  same  animal  with  states  in 
which  there  is  almost  complete  focalization  upon  one  prom- 
inent conscious  experience. 

Speaking  figuratively,  the  consciousness  of  the  lower 
animals  may  be  like  a  drop  of  ink  when  focalized,  and  like 
the  same  drop  of  ink  spread  over  a  surface  when  there  is 
no  focalization;  while  a  highly  developed  human  conscious- 
ness is  like  a  kaleidoscopic  view,  always  presenting  unified 
variety  that  changes  with  every  change  of  attention,  yet 
is  always  a  complex  and  distinct  unity. 

Note.  —  It  is  often  emphasized  that  the  subjective  phenomena 
occurring  after  physical  stimulations  and  neural  activity  are  entirely 
new  and  in  no  respect  like  their  supposed  cause.  Such  a  statement, 
when  looked  at  in  the  light  of  scientific  observation  in  other  fields, 
would  seem  to  be  scarcely  worthy  of  the  mention  and  certainly  not 
of  the  attention  which  it  has  received.  In  all  scientific  investiga- 
tions new  phenomena  that  have  no  resemblance  to  their  causes  are 
appearing.  There  is  no  resemblance  between  a  blow  on  a  piece  of 
rock  and  the  spark  that  results.  In  all  chemical  combinations  the  in- 
troduction of  a  new  element  or  condition  may  call  forth  a  phenomenon 
that  bears  no  resemblance  to  the  element  occasioning  it.  The  new 
phenomena  of  neural  activity  are  as  different  from  the  stimulus 
calling  them  forth  as  are  the  conscious  states  that  follow  and  accom- 
pany the  neural  activity.  The  peculiar  thing  about  the  new  phe- 
nomena of  consciousness  that  appear  as  the  result  of  nervous  activity 
in  the  human  cortex  is  not  that  they  in  no  respect  resemble  the 
physical  stimulus  nor  the  physiological  activity,  but  that  the  new 


CONSCIOUSNESS  211 

phenomena  appear  only  to  the  consciousness  of  the  individual  pos- 
sessing the  nervous  structure  thus  stimulated.  Other  consciousnesses 
may  have  corresponding  or  similar  facts  just  as  other  worlds  may 
have  the  same  elements  as  our  own  earth,  but  direct  examination  of 
them  is  possible  only  for  the  individual  to  whose  world  they  belong. 
Just  as  the  organism  is  a  unity  and  all  of  its  behavior  is  governed  by 
the  necessity  of  preserving  that  unity  amidst  external  influences  of 
various  kinds,  so  the  inner  conscious  life  is  a  unity  and  all  that  takes 
place  in  it  has  reference  to  its  own  preserv^ation  and  development. 
With  the  appearance  of  a  highly  developed  consciousness,  as  has 
already  been  suggested,  the  objective  factor  in  evolution  —  natural 
selection  —  is  replaced  by  the  subjective  factor  of  pleasure  and  pain, 
and  the  development  of  the  individual  be  havior  is  governed  by  con- 
scious selection  of  the  most  effective  reactions.  In  the  simpler  forms 
of  mental  life  there  is  little  subjective  activity  that  is  not  manifested 
in  objective  movement,  but  in  a  highly  developed  human  mind  a 
large  part  of  the  subjective  life  is  not  manifested  outwardly  in  be- 
havior, though  it  may  be  indicated  by  words;  hence  there  are  extensive 
fields  of  consciousness  to  be  studied  in  human  beings  besides  that  of 
objective  behavior,  which  is  common  to  men  and  animals.  This  is 
the  distinctive  field  of  psychology,  and  its  problem  is  to  determine 
how  activities  are  related  to  each  other  in  individual  consciousness, 
and  not  to  wonder  at  or  dispute  over  the  fact  that  the  phenomena  of 
consciousness  are  different  from  those  of  physics  or  physiology. 


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212  GENETIC   PSYCHOLOGY 

*DowNEY,  June.    Automatic  Phenomena  of  Muscle  Reading,  Jr. 

Phil.  Psych,  df  Sci.  Meth.,  Vol.  V,  pp.  650-658. 
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Science,  Vol.  XVI,  pp.  1-12. 
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/ 


CONSCIOUSNESS  213 

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CHAPTER    VIII 

SPECIFIC   CONSCIOUS   STATES   OF   ANIMALS   AND 
MAN 

GENERAL  CHARACTER   OF   FEELING   IN   ANIMALS 

Even  the  lowest  forms  of  animal  life  show  two  kinds  of 
reaction,  negative  and  positive.  Where  a  creature  pos- 
sesses consciousness  these  two  forms  of  reaction  are  doubt- 
less correlated  with  feelings  of  the  disagreeable  and  the 
agreeable.  It  may  be  asserted  that  the  feelings  of  the 
agreeable  and  the  disagreeable  are  results  instead  of  causes 
of  the  increase  or  decrease  of  activity  associated  with  them. 
This  is  doubtless  true  to  a  certain  extent,  but  it  is  reasonable 
to  suppose  that  the  feelings  exert  a  reciprocal  influence 
upon  the  physiological  activities ;  otherwise  there  would  be 
no  reason  for  creatures  possessing  consciousness  to  be  se- 
lected for  survival,  and  consciousness  could  never  have 
become  such  a  prominent  characteristic  as  we  know  that 
it  has  become  in  man. 

Feelings  of  attraction  and  repulsion  are  doubtless  promi- 
nent features  of  the  consciousness  of  all  animals  that  learn 
quickly.  These  do  not  necessarily  involve  any  definite 
representation  of  what  is  to  be  experienced.  We  have 
an  impulse  to  touch,  pick  up,  or  eat  some  objects  and  to 
draw  away  from  others,  without  any  distinct  representa- 
tion of  the  results  of  such  movements.  It  is  only  when 
we  delay  a  movement  that  we  are  likely  to  form  images  of 

214 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN     21 5 

results  to  be  obtained.  In  animals,  conscious  represen- 
tation is  doubtless  even  less  prominent  in  such  cases  than 
in  man. 

Even  strong  emotions,  such  as  fear  and  anger,  which 
appear  to  be  manifested  in  some  form  in  all  animals,  are 
probably  entirely  different  in  their  consciousness,  when 
they  possess  any,  from  what  they  are  in  ours.  Fear  in 
man  is  largely  a  matter  of  imagination,  while  in  animals 
it  is  chiefly  a  form  of  reaction.  A  person  who  is  actively 
getting  out  of  harm's  way  usually  feels  at  the  time  merely 
increased  activity.  It  is  only  when  one  is  keeping  still, 
or  relatively  so,  and  representing  what  may  happen  or 
has  happened,  that  he  suffers  acutely  from  fear.  Men 
of  action  suffer  very  little  from  fear.  When  danger 
threatens  they  act,  and  when  it  does  not,  they  do  not  think 
about  it.  This  is  true  of  animals,  only  in  a  greater  degree. 
However  often  a  wild  animal  may  be  frightened,  as  soon 
as  the  heightened  activities  become  normal,  he  appears  to 
be  entirely  comfortable  till  another  danger  stimulus  is 
received.  What  is  true  of  fear  is  also  true  to  a  large  extent 
of  anger. 

The  so-called  "grief"  of  animals  is  also  largely  motor 
rather  than  psychic,  as  it  is  also  in  some  people.  An  im- 
portant object  of  activity  is  lacking  when  a  companion  or 
a  master  is  taken  away,  and  apathy,  or  a  wild  form  of  un- 
directed acti\'ity,  is  likely  to  take  the  place  of  the  orderly, 
directed  activity  that  has  been  concerned  with  the  absent 
individual.  A  horse  may  be  as  much  disturbed  by  the 
absence  of  a  mate  with  whom  he  fights  a  great  deal,  as  of 
one  with  whom  he  is  on  good  terms.  A  new  object  of 
activity  is  the  best  solace  for  grief  in  men  and  animals. 


2l6  GENETIC   PSYCHOLOGY 

because  it  substitutes  directed  for  undirected  activity. 
It  also  gives  less  opportunity  for  the  representative  activity, 
which  is  so  likely  to  be  carried  on  by  man,  and  which  in  him 
is  the  chief  source  of  emotion.  The  readiness  with  which 
grief  may  be  consoled  in  some  instances  is  well  illustrated  by 
Morgan's  incident  of  the  cow  that  was  frantic  because  her 
calf  had  been  taken  away  but  was  quieted  by  a  stuffed 
calf  to  lick,  and  was  soon  calmly  engaged  in  eating  the  hay 
with  which  it  was  stuffed. 

Similar  statements  might  be  made  of  other  forms  of 
instinctive  emotion.  Animals  are  supposed  to  show 
sympathy  for  wounded  companions,  but  the  reaction  is 
largely  motor  rather  than  mental,  as  is  also  sometimes 
the  case  in  man.  The  smell  of  blood  greatly  excites  a  herd 
of  cattle,  and  if  the  enemy  that  spilled  the  blood  of  a  com- 
rade is  seen,  it  may  be  fiercely  attacked ;  but  if  it  is  not  found 
it  is  not  unusual  for  the  excitement  to  expend  itself  upon 
the  wounded  individual.  In  their  primitive  form  instinc- 
tive emotions  are  merely  native  tendencies  to  act  in  certain 
ways  under  certain  circumstances,  and  only  when  represen- 
tation takes  the  place  of  action,  either  for  the  time  being 
or  permanently,  do  they  become  genuine  emotions  involv- 
ing intense  feelings. 

The  above  statements  do  not  mean  that  animals  do  not 
experience  any  emotions  in  connection  with  their  instinc- 
tive acts,  or  that  man  experiences  none  when  he  imme- 
diately makes  the  instinctive  movements.  Where  the  de- 
velopment of  a  situation  does  not  lead  too  quickly  to  the 
instinctive  reaction,  anticipatory  images  may  be  formed  by 
animals  as  a  result  of  a  series  of  stimuli  which  cause  them 
to  feel  as  well  as  to  act.     On  the  other  hand,  when  men 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN     21 7 

arc  making  instincti\'c  reactions  that  arc  not  too  vigorous, 
the  apparatus  concerned  in  imaging  may  also  be  suffi- 
ciently active  to  produce  strong  emotional  states.  The 
point  to  be  emphasized  is  that  in  both  men  and  animals 
prompt  and  unimpeded  instinctive  reaction  doubtless  has 
less  feeling  accompanying  it  than  when  there  is  delay, 
obstruction,  and  conflict  of  motor  tendencies,  with  more  or 
less  imaging  of  some  sort. 

It  must  not  be  supposed,  however,  that  since  represen- 
tation is  necessary  to  emotion  the  feeling  is  strongest  when 
representation  is  most  definite.  On  the  contrary,  defi- 
nite and  specific  representation,  like  prompt  imobstructed 
movement,  may  be  accompanied  by  less  feeling  than  less 
clearly  defined  imagery.  It  is  generally  true  that  an 
emotion  is  stronger  when  the  general  character  of  what 
is  to  happen  is  anticipated,  but  not  definitely  known  and 
specifically  represented.  This  is  especially  true  in  fear, 
for  unknown  dangers  produce  more  agonizing  fears  than 
any  known  consequence  that  can  be  clearly  represented. 
In  man  there  are  a  great  variety  of  emotions  associated 
with  imagery  that  are  probably  entirely  unknown  to  ani- 
mals. ]\Ian  has  emotions  also  associated  with  concepts, 
but  except  as  the  concepts  are  accompanied  by  concrete 
images  the  emotions  are  not  likely  to  be  intense. 

PAIN 

Pain  as  a  sensation  is  probably  a  difi"erentiation  of  the 
feeling  of  the  disagreeable  which  serves  as  a  stimulus  to 
negative  reactions.  In  man,  ])ain  sensations  are  differen- 
tiated from  states  that  are  disagreeable,  and  there  is  some 


2l8  GENETIC   PSYCHOLOGY 

ground  for  claiming  that  physiologically  they  are  due  to 
the  excitation  of  specific  nerve  elements.  To  what  extent 
pain  sensations  in  animals  are  differentiated  from  the 
generally  disagreeable  we  do  not  know,  nor  is  it  possible 
to  assert,  without  fear  of  contradiction,  how  the  intensity 
of  pain  in  animals  compares  with  that  in  man.  We  can 
reason  as  to  the  probabilities  of  the  case  from  the  function 
of  pain  in  promoting  self-preservative  reactions  and  the  part 
it  plays  in  our  own  lives. 

Pain,  like  the  general  feeling  of  the  disagreeable,  serves 
as  a  stimulus  to  do  something  to  obtain  relief.  The  re- 
actions to  pain  stimulation  are  usually  of  a  trial  character, 
and  experiment  shows  that  in  man,  reactions  to  pain 
sensations,  though  more  vigorous,  are  slower,  less  dis- 
criminative, and  less  accurate  than  to  stimuli  that  have  a 
suggestive  value.  Fine  discrimination  of  suggestive  stim- 
uli which  are  neither  agreeable  nor  disagreeable,  and 
accurate  and  prompt  response  to  such  stimuli,  are  the 
most  effective  means  of  avoiding  painful  stimuli  and  of 
preserving  life.  Painful  stimulations  best  serve  their 
function  when  they  produce  many  varied  and  vigorous 
movements,  by  means  of  one  or  all  of  which  relief  may  be 
obtained.  Fine  discrimination  as  to  the  degree  and  qual- 
ity of  pain  would  not  be  of  great  value  after  the  unfavorable 
stimulus  had  already  begun  to  act.  It  matters  not  whether 
pain  is  caused  by  heat,  cold,  or  contact.  The  only  thing 
to  do  is  to  get  away  from  the  painful  stimulus,  while 
successful  reaction  to  a  suggestive  stimulus  involves  ac- 
curate discrimination.  It  does  not  follow  therefore  that, 
because  a  creature  reacts  very  quickly  and  accurately  to 
a  stimulus,  it  is  experiencing  pain.     Pain  is  more  prob- 


SPKCIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN     219 

ably  present  when  the  reactions  are  varied  and  vigorous 
than  when  rapid  and  finely  adjusted.  It  is  not  to  be  sup- 
posed, however,  that  the  pain  is  always  proportional  to  the 
vigor  of  the  reactions.  It  is  true  of  ourselves  only  within 
certain  limits  that  the  greater  the  pain  the  more  vigorous 
the  reaction.  Vigorous  reaction  probably  serves  of  itself 
as  a  relief  from  the  slighter  stimuli,  but  when  the  pain 
becomes  intense,  relief  cannot  thus  be  obtained  and  there 
is  often  marked  decrease  in  physiological  activity  as  well 
as  of  movements.  This  decreased  activity  probably  serves 
to  decrease  the  capacity  to  feel  pain. 

One  means  of  judging  of  the  relative  importance  of 
sensory  stimuli  is  to  observe  what  stimulus  dominates 
action  when  several  are  being  given.  This  furnishes 
something  of  a  basis  for  comparison  between  men  and 
animals.  It  is  a  well-known  fact  that  a  severe  wound  in 
man  produces  loss  of  appetite  and  less  ready  response  to 
all  forms  of  external  stimulation.  This  is  true  to  some 
extent  of  the  higher  animals  and  to  only  a  slight  extent  of 
the  lower.  A  shark  or  a  bee  may  continue  to  feed  after  a 
considerable  portion  of  the  body  has  been  cut  away  so  that 
the  food  cannot  be  retained.  Frogs  and  fishes  will  again 
and  again  take  a  bait  though  severely  lacerated  by  the 
hook  each  time  they  do  so.  These  facts  indicate  that  pain 
does  not  play  such  a  prominent  part  in  determining  the 
activity  of  animals  as  of  men. 

Vigorous  and  varied  movements  may  be  the  result  of 
the  overwhelming  dominance  of  a  painful  sensation,  or  they 
may  result  merely  from  a  disturbance  of  equilibrium  in 
the  relation  of  part  to  part,  upon  which  definite  movements 
depend.     The  latter  rather  than  the  former  is  almost  surely 


220  GENETIC    PSYCHOLOGY 

the  explanation  of  tlie  beha\'ior  of  the  angleworm  when 
cut  in  two.  If  cut  in  two  (juickly,  while  crawling,  the  front 
part  is  likely  to  continue  to  move  forward  as  if  nothing 
had  hap])ened,  while  the  posterior  portion  curls  up  and 
makes  all  kinds  of  irregular  movements,  after  which  it  may 
move  in  the  opposite  direction.  If  this  portion  is  again 
cut  in  two  the  part  that  is  leading  continues  to  move  for- 
ward while  the  part  that  is  following  makes  irregular  move- 
ments. This  is  because  each  segment  in  crawling  responds 
to  the  stimulus  of  the  segment  in  front  of  it,  and  when  that 
is  removed  equilibrium  is  destroyed  and  movements  are 
very  irregular.  Injuries  on  one  side  of  the  cerebellum  in 
higher  animals  produce  for  a  similar  reason  incoordinated 
or  "forced"  movements  of  the  whole  body. 

Putting  these  facts  together  it  seems  quite  probable  that 
pain  in  animals  is  not  clearly  differentiated  from  the  feeling 
of  the  disagreeable,  and  that  the  feeling  is  less  intense  the 
lower  we  go  in  the  scale  of  animal  life.  Man  probably 
experiences  pain  in  a  distinct  and  intense  form  more  than 
any  other  creature,  and  the  more  highly  developed  man 
more  than  those  with  less  highly  developed  nervous  or- 
ganizations. Idiots  are  frequently  so  insensitive  to  pain 
that  what  would  be  a  severe  surgical  operation  to  a  normal 
individual  appears  to  be  to  them  merely  an  interesting 
and  novel  experience. 

It  is  probable  that  pain  is  a  prominent  feature  in  the 
mental  life,  not  so  much  because  of  the  value  of  the  sen- 
sation in  itself  in  the  preservation  of  life  and  health,  as 
because  of  its  relation  to  other  mental  states.  The  gen- 
eral refinement  of  nervous  organization  in  man  is  probably 
necessarily  correlated  with  some  increase  in  sensitiveness 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN    221 

to  painful  stimuli.  It  is  probable  also  that  more  intense 
feelings  of  pain  are  needed  in  man  to  prevent  actions  that 
are  not  for  the  good  of  his  body,  than  in  animals,  nearly 
all  of  whose  conscious  states  are  related  to  their  physical 
well-being.  In  man,  as  we  shall  see  later,  there  are  many 
positive  feelings  of  pleasure  stimulating  him  to  do  things 
that  are  not  for  the  good  of  the  body  and  may  possibly 
be  of  injury  to  it.  A  very  slight  disagreeable  feeling  of 
hunger  may  be  sufficient  to  insure  that  an  animal  shall  take 
food,  but  a  very  much  greater  feeling  of  discomfort  may 
be  needed  to  induce  a  man  to  cease  the  interesting  occupa- 
tion of  painting  or  writing  in  order  to  partake  of  food. 
It  is  probably  because  man  is  capable  of  experiencing  so 
many  more  agreeable  feelings,  that  are  not  of  great  biologi- 
cal value,  than  are  animals,  that  he  is  capable  of  expe- 
riencing more  intense  feelings  of  pain,  because  they  are 
needed  in  order  to  preserve  a  proper  balance  and  induce 
him  to  act  with  reference  to  bodily  needs  as  well  as  with 
reference  to  mental  pleasures. 

Those  who  read  into  the  actions  of  animals  the  same 
degree  of  suffering  of  which  they  are  themselves  capable, 
are  probably  wholly  misinterpreting  the  phenomena. 
On  the  principles  of  evolution  we  can  see  no  reason  why 
great  capacity  for  suffering  should  be  of  any  use  to  the 
lower  animals,  and  being  of  no  use,  there  is  no  reason  to 
suppose  that  such  capacity  would  have  been  developed 
by  natural  selection.  All  that  is  needed  in  the  way  of 
painful  experience  in  the  life  of  animals  is  a  feeling  of  dis- 
comfort strong  enough  to  produce  vigorous  action  when  an 
unfavorable  stimulus  is  being  received,  and  to  dominate 
behavior  in  so  far  as  the  well-being  of  the  body  demands 


222  GENETIC    PSYCHOLOGY 

that  it  shall  dominate.  In  man,  however,  aesthetic,  moral, 
and  religious  feelings  often  produce  action  injurious  to 
the  body,  even  in  the  face  of  pain  which  prompts  to  beha- 
vior favorable  to  bodily  needs. 

INTELLECTUAL   STATES 

Sensations 

In  man,  sensations  have  the  quality  of  being  not  only 
painful  or  pleasurable,  or  at  least  agreeable  or  disagreeable, 
but  they  have  many  other  qualities  by  which  the  sensa- 
tions due  to  one  sense  organ  are  distinguished  from  those 
caused  by  the  stimulus  of  other  sense  organs.  In  addition 
to  this,  difference  in  sensations  due  to  different  stimulat- 
ing objects  affecting  the  same  sense  organ,  is  clearly  dis- 
criminated, e.g.  various  colors  by  the  eye  and  many  odors 
by  the  nose.  We  are  confronted  with  the  question  as  to 
how  far  animals  discriminate  in  consciousness  the  dif- 
ference between  the  results  of  stimulation  of  the  different 
sense  organs  and  between  the  different  kinds  of  stimuli 
affecting  the  same  organ.  In  trying  to  answer  this  question 
we  should  consider  our  least  highly  developed  senses  rather 
than  those  that  are  most  highly  developed,  and  especially 
than  those  giving  characteristic  sensations  that  have  been 
named  and  specifically  analyzed  and  separated  from  the 
general  mass  of  sensations  accompanying  them. 

Touch,  taste,  and  smell  are  the  least  highly  developed 
of  our  senses  and  are  by  us  least  accurately  discriminated, 
and  hence  are  most  profitably  studied  as  a  basis  for  under- 
standing the  mental  states  of  animals.  In  many  of  our 
experiences  we  are  conscious  of  the  effects  of  the  stimula- 
tion of  one  or  more  of  these  senses  without  knowing  ac- 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN     223 

curately  which  ones  are  affected.  When  we  drink  coffee 
or  eat  ice  cream,  we  say  that  the  taste  is  agreeable  or  dis- 
agreeable, when  in  reality  the  feeling  that  we  experience 
is  due  to  the  stimulus  of  three  senses  instead  of  one.  If 
the  temperature  of  these  objects  is  changed,  we  realize  that 
their  agrecableness  or  disagrecableness  depends  largely 
upon  tactile  sensations,  while  if  we  have  a  severe  cold,  we 
find  that  one  of  the  essential  qualities  of  agrecableness, 
that  of  flavor,  is  lacking,  because  the  sense  of  smell  is  not 
acting  effectively.  Because  of  our  varied  mental  life  we 
are  able  by  practice  and  effort  to  analyze  the  complex 
mental  state  produced  by  simultaneous  stimulation  of  all 
of  these  senses  into  sensations  having  the  qualities  of 
sweetness,  bitterness,  saltiness,  sourness,  warmth,  cold- 
ness, smoothness,  roughness,  and  into  a  variety  of  odor 
sensations.  In  our  ordinary  experience,  however,  we 
make  very  few  of  these  analyses. 

The  ordinary  individual  notices  in  eating  that  the  food 
is  agreeable  or  disagreeable,  and  sometimes  recognizes 
that  it  has  some  quality  which  he  likes  in  food  or  that  that 
quality  is  not  present,  and  yet  there  is  no  complete  and 
clear  analysis  of  just  what  the  quality  is.  One  who  has 
given  no  attention  to  cookery  may  say  that  the  cake  is  not 
good,  realizing  that  it  lacks  some  essential  quality,  but  be 
utterly  unable  to  tell  what  that  quality  is,  though  the  cook 
who  has  given  attention  to  such  things  may  say  at  once, 
"It  has  not  enough  salt,"  or  "It  is  not  sweet  enough." 
Even  an  experienced  cook  may,  however,  detect  a  lack  with- 
out knowing  at  once  what  is  missing,  e.g.  a  lady  said  that 
something  was  lacking  in  her  lemon  pie,  and  later  remem- 
bered that  she  had  not  as  usual  put  salt  into  the  filling. 


224  GENETIC    PSYCHOLOGY 

Where  varied  experiences  and  practical  needs  have  made 
it  convenient  to  analyze  complex  sensations  into  their  ele- 
ments, such  analyses  have  been  made,  but  not  otherwise. 
One  of  the  most  common  mistakes  in  attempting  to  inter- 
pret the  mental  states  of  creatures  whose  experience  and 
needs  are  different  from  our  own  is  in  supposing  that  ele- 
ments of  mental  states,  which  we  have  analyzed  from 
the  complex  in  which  they  are  always  found,  have  also  been 
analyzed  by  them.  This  vitiates  the  reasoning  of  many 
writers  on  animal  behavior  as  well  as  that  of  many  writers 
on  general  psychology.  A  mental  state  becomes  an 
entirely  different  mental  state  after  it  has  been  analyzed 
from  what  it  was  before  such  analysis.  All  the  elements 
were  there  at  first,  in  the  total  experience  of  the  whole,  but 
after  the  analysis  they  are  there  as  individual  factors  and 
not  simply  as  influencing  the  general  character  of  the  mental 
state.  A  person  who  prefers  one  picture,  poem,  or  speech 
to  another,  may  have  exactly  the  same  preference  after  he 
has  learned  to  analyze  pictures,  poems,  and  speeches  so 
as  to  know  in  just  what  characteristics  they  differ  from 
each  other ;  but  the  mental  state  produced  by  the  picture, 
poem,  or  speech  will  never  again  be  the  same  as  it  was  be- 
fore such  analysis,  and  soon  he  will  be  unable  to  under- 
stand how  an  individual  who  distinguishes  between  two 
pictures  as  wholes,  can  fail  to  perceive  the  exact  character- 
istics that  he  knows  are  possessed  by  one  and  lacking  in 
the  other.  It  is  this  that  makes  it  so  difficult  for  adults 
to  understand  the  mental  condition  of  children. 

A  soldier  who  does  not  know  a  single  note  may  learn  to 
respond  accurately  to  the  bugle  call,  no  matter  how  many 
other  sounds  are  being  made  at  the  same  time.     If  we 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN    225 

apply  the  same  principle  to  the  behavior  of  animals,  we 
shall  have  to  adopt  an  entirely  different  principle  of  inter- 
pretation from  that  taken  by  many  writers.  A  striking 
example  of  the  discriminali\-e  ability  of  a  dog  is  given  by 
Romanes.  He  found  that  it  could  follow  his  track,  al- 
though a  dozen  other  men  had  followed  in  his  footsteps 
and  seven  of  them  had  diverged  later  from  the  path  taken 
by  himself  and  the  others.  This  is  interpreted  by  one  of 
the  most  recent  and  acute  students  of  animal  behavior, 
Miss  Washburn,  as  an  instance  of  the  analysis  of  a  sensa- 
tion from  the  complex  in  which  it  occurs,  similar  to  that 
of  the  expert  musician  who  detects  the  instrument  and 
the  exact  error  made  by  a  performer  in  an  orchestra.  To 
the  author  it  does  not  seem  probable  that  the  mental  state 
of  the  dog  in  following  his  master's  track  is  at  all  like  that 
of  the  musician  in  detecting  a  false  note.  The  mental 
state  of  the  dog  is  probably  very  much  more  like  that  of 
the  unmusical  soldier  who  knows  the  bugle  call  for  advance 
of  his  own  regiment,  from  any  other  signal  and  from 
the  same  signal  made  by  another  bugler,  although  he 
knows  not  a  single  element  of  music.  To  the  dog,  the 
sum  total  of  odors  with  that  of  the  master  is  different 
from  any  sum  total  of  odors  in  wliich  tliat  of  the  master  is 
not  included,  hence  he  knows  whicli  track  to  follow.  He 
follows  that  track  just  as  a  man  eats  cake  that  has  the 
(juality  that  he  likes,  although  he  does  not  know  just 
what  the  quality  is;  or  the  reader  still  prefers  the  poem 
that  apjjeals  to  him  rallier  than  the  one  that  does  not, 
although  he  is  utterly  unable  to  tell  the  characteristic  u])on 
which  his  preference  depends. 

The  fact  that  an  animal  acts  differently  when  a  certain 
Q 


226  GENETIC    PSYCHOLOGY 

stimulus  is  present,  even  in  a  very  slight  degree,  from  what 
he  does  when  it  is  absent,  does  not  prove  that  he  has  a 
distinct  sensation  corresponding  to  that  stimulus,  but 
only  that  his  mental  state  in  its  total  character,  when  that 
stimulus  is  present,  is  different  from  what  it  is  when  it  is 
absent.  Nature  provides  the  sense  organs  for  special 
sensations  but  they  come  into  actual  existence  in  conscious- 
ness as  separate  elements  only  when  the  results  of  expe- 
rience make  this  separate  recognition  valuable.  The  fact 
that  Japanese  mice  learn  to  go  in  at  the  entrance  illumi- 
nated with  red  instead  of  one  illuminated  with  green,  does 
not  prove  that  there  is  a  conscious  sensation  of  red  and  of 
green  as  analyzed  elements  in  the  general  mental  state 
involved  in  the  action  being  performed.  The  fact  that  a 
monkey  goes  to  a  box  covered  with  red  instead  of  some 
other  box  for  food,  does  not  prove  that  he  consciously 
discriminates  the  sensation  of  red  as  an  element  in  the  sum 
total  of  his  experience.  It  is  altogether  probable  that 
children  learn  to  discriminate  objects  with  a  specific  color 
from  objects  not  having  that  color,  before  they  analyze  the 
mental  state  produced  by  the  object  and  become  con- 
scious of  redness  as  one  of  its  characteristics. 

So  long  as  red  or  any  other  characteristic  is  simply  part 
of  a  situation  leading  to  food  it  is  not  likely  to  be  recog- 
nized as  an  element  in  itself.  If  its  presence  means  food, 
not  only  under  those  conditions  but  under  a  great  variety 
of  other  conditions,  so  that  it  appears  as  a  part  of  many 
wholes,  notice  may  be  attracted  to  it  specifically.  If  it  ap- 
pears not  only  as  a  means  to  food  but  as  a  means  to  other 
ends,  it  is  still  further  dissociated  from  any  particular 
combination  of  conditions  and  ends.     This  occurs  very 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN     227 

frequently  in  human  beings  who  have  a  great  variety  of 
interests  and  needs,  while  it  occurs  very  rarely  in  even  the 
higher  animals.  It  is  probable,  therefore,  that  none  but  a 
few  specifically  trained  animals  of  the  higher  type  have 
specific  sensations  of  any  kind  such  as  we  have.  The 
various  sensations  that  they  experience  probably  form  a 
complex  similar  to  that  produced  in  us  by  articles  of  food, 
only  less  definite  and  specific  as  to  the  elements  constituting 
the  complex. 

Space  Perceptions 

The  space  sensations  of  animals  rank  in  importance  with 
the  feelings  of  the  agreeable  and  the  disagreeable.  Dis- 
agreeable sensations  as  signs  of  unfavorable  stimuli  are 
valuable  because  they  indicate  the  need  of  doing  something. 
The  thing  to  be  done  usually  involves  some  kind  of  a  space 
reaction.  To  get  relief  the  creature  must  move  in  a  definite 
way  and  the  more  quickly  it  moves  in  the  right  direction 
the  sooner  is  the  reaction  efl'ective.  It  is  therefore  just  as 
important  that  there  should  be  means  of  determining  the 
direction  of  movement  as  it  is  that  there  should  be  a  feeling 
of  the  disagreeable  to  induce  movement. 

In  a  general  way  the  sensations  upon  which  space  re- 
actions depend  are  of  the  same  general  character  as  those 
by  which  equilibrium  is  maintained.  The  sensations  by 
which  equilibrium  is  maintained  vary  with  the  position 
of  the  body  and  the  relation  of  one  part  to  another,  while 
space  reactions  are  usually  made  in  response  to  stimula- 
tions coming  from  objects  in  the  environment.  In  their 
more  primitive  form,  space  reactions  depend  to  a  consid- 
erable extent  upon   inequality  of   stimulation   and   upon 


228  GENETIC   PSYCHOLOGY 

inequality  of  sensitiveness  to  stimulation  in  different  parts 
of  the  body.  A  creature  with  one  portion  of  the  body  as 
sensitive  as  another  and  equally  affected  on  all  sides  by 
light,  heat,  and  other  stimulations  would  have  no  occasion 
for  movement.  Just  as  soon,  however,  as  it  is  stimulated 
more  on  one  side  than  on  the  other  there  is  occasion  for 
spatial  reaction.  A  greater  sensitiveness  on  one  side 
may  also  call  forth  reaction.  When  a  creature  responds 
by  a  different  movement  according  to  the  portion  stim- 
ulated, it  is  reasonable  to  suppose  that  there  is  some  dif- 
ferentiation of  the  sensitive  surface  so  that  the  eft"ect  of 
the  stimulus  is  different.  As  we  have  already  seen,  this 
appears  very  low  in  the  scale  of  animal  life.  These  two 
principles  are  probably  the  basis  of  all  "tropisms." 

Experiment  shows  that  the  lower  animals  are  influenced 
in  a  spatial  way  by  light,  heat,  and  gravity,  sometimes  one 
being  dominant  and  sometimes  another.  The  sensitive- 
ness to  these  different  kinds  of  stimuli  varies  also  with  the 
internal  conditions  of  the  creature,  the  reactions  of  the 
same  animal  being  at  one  time  positive  and  at  another 
negative  to  the  same  stimulus.  It  is  probable  that  such 
changes  are  of  advantage  to  the  creature,  perhaps  at  one 
time  leading  to  food  and  at  another  to  safety  from  enemies. 
We  may  therefore  best  conceive  of  an  animal  as  being 
in  equilibrium  and  motionless  when  all  the  stimuli  tending 
to  produce  movement  are  in  equilibrium.  If  he  is  moving 
and  all  these  stimuli  are  in  equilibrium,  he  continues  the 
same  form  of  movement,  whether  it  be  in  a  straight  line 
or  in  a  circle.  Variations  from  this  motionless  condi- 
tion or  uniform  movement  are  produced  by  any  stimulus 
that  disturbs  the  equilibrium  and  becomes  for  the  time 
being  the  dominant  director  of  activity. 


I 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  :MAN 


229 


Human  experience  may  Ix'  helj^ful  in  forming  an  idea  of 
the  character  of  space  sensation  in  animals.  A  person  who 
has  been  used  to  working  for  many  years  in  a  certain  room, 
facing  in  a  certain  direction,  and  surrounded  by  the  same 
objects,  is  h'kely  to  be  somewhat  disconcerted  if  he  attempts 
to  do  the  same  kind  of  work  facing  another  way  or  with  the 
position  of  objects  in  the  room  changed.  He  does  not  seem 
to  be  rightly  adjusted  to  his  environment  and  prefers  to  re- 
sume his  old  position.  Perhai)s  many  persons  will  ilnd 
the  most  vivid  illustration  of  spatial  adjustments  in  their 
memories  of  having  waked  in  a  bed  in  a  new  position. 

On  the  conscious  side  a  condition  of  equilibrium  in 
relation  to  surrounding  objects  is  accompanied  by  a 
feeling  of  the  agreeable,  while  disturbance  of  ecjuilibrium 
produces  a  feeling  relatively  disagreeable,  although  the 
reaction  may  be  positive  in  its  character  and  secure  an 
agreeable  result.  Space  discrimination  depends  upon  the 
accuracy  with  which  the  various  stimuli  may  be  coordinated 
so  as  to  maintain  proper  relations  between  different  parts 
of  the  body  and  with  various  objects  in  the  environment. 

This  does  not  mean,  however,  that  the  sensations  coordi- 
nated are  represented  separately  and  distinctly  in  conscious- 
ness. Experiment  shows  that  this  is  not  the  case  e\-en  in 
man.  We  are  guided  with  great  precision  by  sensations 
coming  from  the  hand  and  from  the  eye,  without  being 
distinctly  conscious  of  what  those  guiding  sensations  are. 
Experiment  shows  that  space  judgments  are  greatly  in- 
fluenced by  variations  in  sensation  of  which  the  subject  is 
entirely  unconscious.  This  is  especially  true  of  the  move- 
ments of  the  eye  in  bringing  the  image  upon  the  point  of 
clearest  vision,  in  fusing  the  two  images  upon  the  retinae, 


230  GENETIC    PSYCHOLOGY 

and  in  accommodating  for  different  distances  and  degrees 
of  light.  A  certain  sensation  complex  made  up  of  all  the 
stimuli  affecting  us  at  the  moment  means  an  object  in  a 
certain  place  to  be  reacted  to  by  a  certain  kind  of  movement, 
and  any  variation  in  this  complex  calls  for  a  variation  in 
movement,  but  it  is  exceedingly  difficult  for  us  to  become 
conscious  of  the  exact  sensations  by  means  of  which  our 
movements  are  coordinated  and  adjusted.  A  slight 
variation  from  the  usual  in  this  complex  may  disturb  the 
accuracy  of  our  movements  and  the  accuracy  of  our  space 
judgments,  but  we  are  slightly  or  not  at  all  conscious  of  the 
specific  changes  in  sensations  that  are  influencing  our 
spatial  perceptions  and  movements. 

The  effect  of  surrounding  objects  that  have  no  direct  re- 
lation to  the  objects  with  which  we  are  dealing,  has  long 
been  recognized  in  a  practical  way  by  sportsmen.  Tennis 
players  change  sides  because  the  objects  surrounding  the 
tennis  court  within  their  field  of  view  aft'ect  the  playing. 
If  one  were  to  play  for  a  long  time  on  one  side  of  the  court 
only,  he  would  find  it  very  difficult  to  play  on  the  other  side 
without  error.  He  reacts  not  only  to  the  ball  moving  from 
a  certain  point,  in  a  certain  direction,  at  a  certain  rate,  to 
the  net  and  the  side  lines,  and  to  his  own  movements  and 
position,  but  also  to  any  buildings,  trees,  or  spectators  that 
may  be  in  the  neighborhood  of  the  court. 

All  spatial  reactions  are  determined  by  the  sum  total 
of  the  surroundings  affecting  one.  This  is  true  not  only  of 
single  reactions  but  also  of  a  long  series  of  reactions  by 
means  of  which  one  finds  his  way.  Not  only  do  the  sun  and 
wind  and  one's  own  movements  serve  as  guides,  but  all 
objects  characteristic  of  the  environment,  whether  individu- 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN     23 1 

ally  and  specifically  known  or  not.  For  example,  one  who 
has  lived  much  of  his  life  in  a  place  where  roads  usually 
run  according  to  the  points  of  the  compass  generally  uses 
the  roads  as  reference  points  in  guiding  his  movements, 
although  he  may  not  be  aware  of  the  fact.  When  he 
strikes  into  the  timber  from  the  road,  he  is  continually 
judging  his  direction  by  the  relation  of  his  movements  to  the 
direction  in  which  the  road  runs  that  he  has  just  left.  This 
is  true  of  the  writer,  although  he  did  not  realize  it  until  after 
living  for  a  while  in  a  section  of  the  country  where  the 
roads  run  in  every  direction.  In  trying  to  find  why  he 
made  mistakes  in  direction  when  hunting,  he  was  led  to 
ascribe  them  to  the  fact  that  he  somewhat  unconsciously 
used  the  roads  as  guiding  standards  and  was  led  into  error 
because  these  roads  were  entirely  uncertain  in  their  direc- 
tion. Every  individual  who  is  able  to  find  his  way  is 
doubtless  influenced  in  a  similar  manner  by  something  in 
his  environment.  Often  he  docs  not  know  what  it  is  but 
simply  feels  that  this  is  the  direction  to  take,  that  this  is 
north,  or  that  this  way  seems  familiar. 

It  is  probable  that  the  spatial  reactions  of  animals  are 
guided  in  a  similar  way  by  the  objects  characteristic  of  the 
usual  environment  of  their  species  even  though  they  are  not 
individually  familiar.  A  mountain  sheep,  for  example, 
transported  to  a  new  range  of  mountains,  could  doubtless 
find  food  and  avoid  enemies  very  successfully. 

Creatures  very  low  in  the  scale  may  have  their  reactions  to 
specific  objects  in  their  immediate  environment  modified  by 
becoming  accommodated  to  them,  in  a  way  similar  to  that 
by  whicli  man  becomes  used  to  working  in  a  certain  room 
facing  in  a  certain  direction.     This  is  probably  the  explana- 


232  GENETIC   PSYCHOLOGY 

lion  of  what  is  sometimes  called  the  "homing  instinct"  of 
animals  very  low  in  the  scale.  Experiments  show  that 
when  they  are  moved  from  their  usual  environment  they 
find  their  way  back  again.  This  is  probably  because  they 
are  not  in  equilibrium  with  the  new  environment.  They 
make  various  trial  movements,  then  continue  the  movements 
that  help  to  restore  the  equilibrium  until  they  reach  their 
former  position.  In  higher  animals,  such  as  bees,  wasps, 
dogs,  and  pigeons,  the  same  factor  doubtless  exercises  some 
influence. 

The  chief  difference  is  that  in  the  higher  animals  the 
modification  produced  by  all  the  objects  surrounding  the 
place  where  food  has  been  found  is  produced  by  one  or 
two  perceptions  instead  of  by  long  and  repeated  exposure  to 
the  objects.  The  wasp  that  has  left  food  in  a  certain  place 
has,  we  may  say,  been  polarized  with  reference  to  that  spot 
and  the  objects  surrounding  it,  so  that  she  reacts  to  them 
in  a  different  way  from  what  she  does  to  any  other  set  of 
objects.  The  nervous  system  of  the  homing  pigeon  is 
doubtless  polarized  with  reference  to  the  objects  within  the 
neighborhood.  When  carried  many  miles  and  released, 
his  movements  are  often  at  first  of  a  trial  character;  but 
frequently  he  knows  the  general  direction  of  home,  probably 
in  much  the  same  way  as  many  men  are  able  to  tell  with 
considerable  assurance,  as  soon  as  they  step  off  a  train, 
which  w^ay  is  north,  although  they  may  not  know  how  they 
know  it.  In  flying,  the  pigeon  is  also  probably  guided  by 
the  general  character  of  objects  in  the  landscape,  hills, 
forests,  etc.,  in  the  same  way  in  which  his  race  has  reacted 
to  them.  When  he  approaches  the  neighborhood  of  home, 
so  that  any  portion  of  its  familiar  environment  can  be 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN     233 

perceived,  he  finds  that  direction  the  more  agreeable,  and 
thus  guided,  soon  reaches  his  old  home. 

There  is  much  that  is  mysterious  in  the  reactions  of  ani- 
mals in  finding  their  way,  but  probably  nothing  more  mys- 
terious than  in  man's  modes  of  distinguishing  direction.  He 
himself  usually  knows  little  of  the  specific  sensations  that 
guide  him  and  that  are  the  most  important  factors  in  his 
success.  It  has  been  suggested  that  men  and  animals  may 
be  subject  to  magnetic  influences  as  is  the  needle  of  the 
compass,  and  this  is  the  only  explanation  yet  suggested 
of  how  some  individuals  know  in  every  situation  the  points 
of  the  compass. 

When  men  are  able  to  explain  how  they  know  directions, 
it  is  often  by  memory  images;  hence  they  are  inclined  to 
think  that  movements  are  in  general  guided  in  that  way, 
when,  as  a  matter  of  fact,  men  and  all  animals  are  guided 
much  of  the  time  without  conscious  memories  and  by 
sensations  that  have  little  or  no  separate  representation  in 
consciousness.  Guidance  by  images  in  the  form  of  rep- 
resentation of  the  relation  of  roads  or  objects  that  are 
not  in  the  field  of  view  is  often  possible  to  men  but  is 
by  no  means  universal.  Many  people  can  act  very  suc- 
cessfully as  guides  who  cannot  describe  the  course  to  be 
taken.  In  a  similar  way  animals  are  very  skillful  in  finding 
their  way,  though  they  probably  never  image  the  relation 
of  objects  to  each  other  or  mentally  pass  over  a  route. 

Perception  of  Objects 

No  absolute  line  of  distinction  can  be  drawn  ])etween 
sensation  and  perception,  either  when  viewed  objectively 


234  GENETIC    PSYCHOLOGY 

in  the  form  of  stimulus  and  movement  or  as  observed 
subjectively  in  our  own  consciousness.  The  more  im- 
mediate the  effects  of  the  stimulus,  either  favorable  or  un- 
favorable, the  more  are  we  inclined  to  call  them  sensations. 
When,  however,  the  stimulus  is  not  in  itself  especially 
agreeable,  but  is  suggestive  of  something  to  follow  that  is 
significant  for  our  welfare  we  are  more  likely  to  use  the 
word  "perception."  Taste  and  smell  are  more  frequently 
named  as  sensations  than  are  sights  and  sounds,  although  if 
an  odor  or  a  taste  suggests  other  sensations  associated  with 
it  we  may  use  the  term  "  perception."  We  may  also  use  the 
term. "  sensation  "  to  indicate  the  effects  of  visual  and  auditory 
stimulation  when  we  mean  that  the  light,  color,  or  sound  is  in 
itself  agreeable  or  disagreeable  instead  of  signifying  some 
object  that  as  a  whole  is  pleasing  or  otherwise. 

On  the  motor  side  the  movements  in  response  to  sensa- 
tions are  usually  less  complex  and  definitely  coordinated 
than  those  in  response  to  suggestive  stimuli  and  involving 
perception.  In  perception  there  is  not  only  response  to 
the  stimulus  received  but  an  adjustment  to  the  object  or 
situation  suggested  by  it. 

On  the  mental  side  in  perception  there  is  not  simply  a 
feeling  of  agreeableness  or  disagreeableness,  but  a  mental 
attitude  toward  the  situation  or  object  suggested  which  in 
the  higher  animals  may  involve  anticipatory  images  of  what 
is  to  come,  and  in  man  in  a  certain  stage  of  development 
may  arouse  memory  images  of  past  experiences  in  similar 
situations. 

Where  the  response  to  a  stimulus  is  clearly  of  a  reflex  or 
instinctive  character,  we  are  more  likely  to  use  the  term  "  sen- 
sation "  to  describe  the  mental  state  than  when  the  reac- 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN     235 

tion  is  one  that  has  been  acquired  by  previous  experience. 
There  is  no  doubt  that  animals  often  make  fitting  responses 
to  complex  situations  in  an  instinctive  way,  and  hence  may, 
in  one  sense  of  the  word,  be  said  to  have  instinctive  per- 
ceptions. This  is  especially  true  of  what  are  usually  de- 
scribed as  space  perceptions.  Without  i)revious  practice  a 
chicken  can  peck  with  considerable  accuracy  at  a  particle  of 
food,  and  young  pigs  either  seeing  or  hearing  their  mother 
can  guide  themselves  directly  toward  her.  They  can  also 
judge  distance  with  sufficient  accuracy  to  jump  success- 
fully from  a  higher  to  a  lower  position.  The  response 
of  chickens  to  a  danger  call  is  also  evidence  of  instinctive 
perception  if  we  admit  that  the  term  may  be  applied  to  that 
which  is  native  instead  of  limiting  it  to  that  which  has  been 
acquired  by  experience.  It  is  probably  well  to  recognize 
two  kinds  of  perceptions,  the  instinctive  and  the  acquired; 
although  it  may  be  convenient  in  describing  the  behavior 
of  the  higher  animals  and  of  man  to  use  the  term  "per- 
ception" in  the  narrower  sense  of  acquired  perceptual  motor 
reactions  and  tendencies,  while  in  a  still  narrower  sense  it 
refers  only  to  reactions  represented  in  consciousness. 

On  the  mental  side  there  can  be  no  anticipatory  images 
(or  mediated  sensations)  except  in  the  case  of  acquired  per- 
ceptions. There  is  an  instinctive  basis,  however,  c\en  in 
man  for  many  acquired  perceptions.  The  response  of  a 
dog  to  food  placed  in  its  mouth  is  largely  sensory  in  charac- 
ter, althougli  the  swallowing  or  ejecting  of  the  food,  accord- 
ing to  its  character,  suggests  that  there  may  be  some  reac- 
tion to  the  object  as  a  whole  rather  than  simply  to  the 
sensation  that  has  already  been  experienced.  The  response 
of  the  dog  to  the  stimulus  of  the  odor  of  meat  is  of  a  similar 


236  GENETIC   PSYCHOLOGY 

character  but  slightly  more  perceptual.  His  response  to 
meat  that  he  can  see  but  cannot  smell,  if  he  makes  such  a 
response,  is  without  question  an  instance  of  acquired  per- 
ception, though  the  movements  he  makes  are  largely  in- 
stinctive. His  reaction  to  the  sight  of  a  running  cat  indi- 
cates an  instinctive  perception,  but  his  pause  when  the  cat 
turns  and  faces  him  may  indicate  an  acquired  perception 
gained  from  previous  painful  experience  in  a  similar  situa- 
tion. It  is  not  necessary  to  suppose  that  he  has  a  distinct 
memory  of  the  former  experience,  but  merely  that  the  pain 
previously  experienced  in  that  situation  has  modified 
his  instinctive  mode  of  action  and  perhaps  produced  some 
vague  anticipatory  images  of  disagreeable  results  that  may 
follow  continued  pursuit. 

In  our  own  experience  we  acquire  new  modes  of  behavior 
without  any  distinct  recognition  of  the  exact  changes  made 
and  their  results.  This  is  perhaps  best  illustrated  by  the 
experience  of  one  who  is  learning  to  ride  a  bicycle.  He 
learns  to  make  certain  adjustments  and  avoid  others 
without  knowing  just  how  he  does  it. 

In  the  case  of  more  sudden  and  marked  modifications 
the  attitude  and  feeling  toward  an  object  may  persist  long 
after  it  is  impossible  to  recall  any  former  experience  with  it. 
This  is  well  illustrated  by  a  case  mentioned  by  Professor 
Judd  of  a  man  who  was  very  much  afraid  of  horses  without 
knowing  why.  Inquiry  revealed  the  fact,  however,  that  he 
had  been  severely  bitten  by  a  horse  when  he  was  a  small 
boy.  One's  feeling  of  liking  or  dislike  for  persons,  places, 
names,  and  things,  that  cannot  be  accounted  for  by  any 
memories  of  experiences  with  them,  is  doubtless  due  to 
similar   causes.     Attitude    toward    objects    as    shown    in 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN     237 

perceptions  is  much  more  fundamental  than  memory,  being 
produced  in  creatures  incapable  of  memory  and  persisting 
in  higher  creatures  long  after  memory  has  failed. 

Again,  a  child  who  has  seen  a  companion  make  an 
exclamation  or  gesture  of  horror  at  being  touched  or 
approached  by  a  worm  or  a  spider,  may  have  its  attitude 
towards  those  creatures  completely  changed,  although  it  re- 
tains no  memory  of  the  experience  that  produced  the  change. 
It  is  probable  that  nearly  all  the  acquired  perceptions  of 
animals  are  of  this  type  in  which  there  is  no  memory  of  the 
past  experience,  but  only  a  mental  attitude  of  attraction  or 
repulsion  excited  by  the  object,  with  possibly  some  anticipa- 
tory images  of  the  general  character  of  the  result  to  be  ob- 
tained as  agreeable  or  disagreeable. 

In  man,  in  addition  to  these  characteristics  of  perception, 
there  are  often  definite  images  of  just  what  is  to  be  expe- 
rienced, and  sometimes  memory  images  of  former  ex- 
perience. These,  in  the  cases  of  delayed  perception,  which 
are  most  readily  observed,  are  usually  the  prominent 
elements.  Hence  there  is  a  tendency  for  psychologists  to 
ignore  the  less  prominent  phases  of  perception  and  to 
attempt  to  explain  the  perceptions  of  animals  in  terms  of 
definite  images  and  memories.  As  a  result  of  acquired 
perceptions  a  change  in  the  adjustment  of  the  nervous  and 
muscular  apparatus  has  been  produced  so  that  the  creature 
is  modified  and  his  states  of  consciousness  are  changed ; 
but  there  is  no  reason  to  suppose  that  animals  are  conscious 
that  these  changes  have  taken  place.  In  man,  such  a 
consciousness  is  probably  lacking  in  the  majority  of  his 
perceptions.  We  are  surprised  at  the  sensation  we  get 
when  we  take  salt  from  the  sugar  bowl,  but  this  does  not 


238  GENETIC    PSYCHOLOGY 

necessarily  mean  that  before  tasting  we  had  formed  an 
image  of  the  sweet  taste  to  be  experienced.  We  are  often 
surprised  at  the  weight  of  objects,  although  we  are  not 
conscious  of  having  formed  an  image  of  their  weight. 

In  general,  the  changes  in  acquired  perception  are  in  the 
reaction  and  attitude  toward  the  situation  as  a  whole,  but 
where  one  feature  dominates  the  situation  the  change 
may  be  chiefly  with  reference  to  that  one  element.  In  such 
a  case  the  object  or  sensation  may  excite  the  same  reaction 
whenever  experienced.  A  dog  that  has  been  whipped  by 
his  master  when  hunting  may  show  signs  of  fear  when  he 
sees  the  whip  in  the  master's  hand  at  home,  or  perhaps  when 
he  sees  it  in  the  hand  of  any  person.  It  is  not  likely, 
however,  that  he  will  show  any  fear  of  it  when  it  is  not  in  the 
hands  of  some  person,  and  then  perhaps  only  when  it  is 
being  held  or  moved  in  a  certain  way.  In  the  case  of 
acquired  reactions  to  the  more  direct  stimulus  of  an  odor, 
which  is  in  a  way  a  sample  of  the  object  itself,  the  reaction 
is  likely  to  be  of  a  specific  kind  no  matter  what  the  situation 
is  when  that  odor  is  experienced.  A  horse  that  is  gun  shy 
may  show  fear  at  sight  of  a  gun  only  when  it  is  being 
pointed,  but  if  his  fear  is  due  to  the  odor,  it  is  more  likely  to 
be  aroused  by  that  alone,  whatever  the  situation. 

Images  and  Memories 

Since  the  actions  of  all  creatures  are  dominated  by  the 
end  to  be  gained,  and  since  association  of  impressions  is 
much  stronger  in  the  order  in  which  they  occurred  than  in 
the  reverse  order,  it  is  clear  that  anticipatory  images  would 
be  formed  easier  and  earlier  than  reminiscent  images. 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN     239 

Where  a  stimulus  is  always  immediately  followed  by  the 
same  movement,  there  is  not  in  our  own  case  any  conscious 
image  formed  and  there  is  no  reason  to  see  why  there  should 
be  in  the  case  of  any  creature.  When  movements  are 
directed  toward  an  end  but  \-ary  in  ways  that  result  in 
reaching  that  end  by  shorter  means,  as  is  the  case  in  the 
learning  of  many  of  the  higher  animals,  it  would  seem  that 
an  image  of  the  result  to  be  obtained  may  be  dominating 
the  movements.  If,  however,  the  movements  follow  the 
stimulus  immediately,  it  is  difficult  to  see  how  an  image 
could  be  formed,  or  be  of  any  service  if  formed. 

An  animal  that  is  stimulated  by  objects  at  a  distance,  as, 
for  instance,  a  deer  by  the  form  of  a  hunter,  may  not  make 
any  considerable  reaction  to  that  stimulus  for  some  time. 
It  may  wait  until  the  stimulus  is  repeated  and  intensified 
by  nearer  approach  and  perhaps  supplemented  by  sound  or 
odor  before  it  reacts  strongly  by  running  away.  Evidently 
the  conditions  in  this  case  are  favorable  for  the  production 
of  modifications  in  portions  of  the  nervous  system  not 
directly  connected  with  the  motor  centers,  and  hence  for 
the  formation  of  images.  Such  images  of  results  that 
may  follow  the  various  stimuli  being  received  from  ob- 
jects at  a  distance  would  be  likely  to  be  of  service  in 
directing  movements.  We  should  expect  therefore  that 
images  of  some  sort  would  be  formed  in  response  to  sug- 
gestive stimuli,  especially  when  immediate  movement  is  not 
necessary,  rather  than  in  response  to  direct  stimuli  and  to 
suggestive  stimuli  requiring  immediate  response.  The 
images  excited  in  the  deer,  however,  are  probably  anticipa- 
tory and  of  tlie  same  type  as  secondary  sensations  or  per- 
ceptual images.     In  order  to  become  free   images   they 


240  GENETIC   PSYCHOLOGY 

must  appear  under  various  circumstances  and  must  be 
aroused  in  some  other  way  than  by  associated  sensory 
activity.  Most  of  our  free  images  are  from  the  sugges- 
tive senses  of  sight  and  hearing,  while  images  of  taste 
and  pain  are  rare,  and  to  many  persons  impossible.  In 
the  case  of  the  suggestive  senses  an  image  of  the  sen- 
sation to  be  experienced  may  serve  the  same  purpose 
as  the  movements  by  which  the  sensation  could  be 
secured;  hence  the  power  of  forming  such  images  has 
been  highly  developed,  while  that  of  forming  images  of 
immediate  sensations  has  been  but  slightly  developed. 

In  learning,  images  sometimes  play  a  prominent  part. 
Where  the  process  of  learning  is  very  gradual,  there  is  no 
reason  to  suppose  that  images  aid  in  the  process,  for  they 
do  not  in  our  own  case.  When,  however,  all  useless  and 
indirect  movements  are  dropped  as  soon  as  the  successful 
one  has  been  made  once,  it  is  probable  that  images  aid  in 
the  process  of  learning.  The  service  rendered  by  images 
must  be  still  greater  when  all  movements  are  inhibited 
for  a  time  and  then  the  right  one  made  at  once.  In  all  but 
the  higher  animals  learning  seems  to  be  a  very  gradual 
process.  Hence  there  is  no  reason  to  suppose  that  images 
play  any  considerable  part  in  the  learning  of  lower  animals. 
Much  of  the  learning  of  monkeys,  raccoons,  and  other  of 
the  higher  animals  and  some  of  that  of  human  beings  is  not 
rapid  enough  to  indicate  that  images  assist  in  the  process. 

In  Cole's  experiments  the  raccoons  learned  to  get  up  on 
the  box  for  food  when  white,  orange,  and  blue  cards  were 
shown  successively,  but  to  remain  down  when  blue  was 
shown  three  times  in  succession.  In  other  words,  the 
reaction  was  not  made  to  blue  alone  or  blue  repeated  three 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN    241 

times  in  succession,  l)ut  only  when  it  was  preceded  by  white 
and  orange.  The  animals  often  began  to  get  up  on  the 
box  after  white  appeared,  which  suggests  that  they  had  an 
anticipatory  image  of  what  was  to  follow.  This  is  perhaps 
further  indicated  by  the  fact  that  they  would  sometimes 
get  down  and  wait  for  the  blue  to  appear  before  getting 
up  on  the  box  again.  It  is  not  certain,  however,  that  this 
indicates  a  definite  image  of  just  w'hat  was  to  appear.  It 
may  be  interj)rcte(l  merely  as  an  indefinite  image  of  pleas- 
ant results  to  be  obtained,  with  a  waiting  for  the  proper 
signal,  which  is  recognized  when  it  appears,  though  it  may 
not  have  been  imaged  previously.  It  is  certainly  true  of 
persons  that  they  are  able  to  anticipate  and  react  to  the 
proper  signal  when  it  appears  wdthout  having  held  in  mind 
an  image  of  it.  The  pause  involved  in  waiting  for  the 
proper  stimulus  is  doubtless,  how^ever,  a  favorable  condition 
for  developing  an  image  of  the  stimulus  that  is  to  appear. 
Whether  such  an  image  actually  is  developed  in  the 
consciousness  of  the  raccoon  cannot  be  stated  positively. 

Should  an  image  be  formed  under  such  circumstances  as 
stated  above  it  would  not  necessarily  be  a  free  image  or 
reminiscent  image,  since  it  is  brought  into  mind  only,  as 
fax  as  can  be  judged,  by  the  general  conditions  of  the  ex- 
periment and  the  immediately  preceding  stimulus  of  white 
and  orange  cards.  Where  an  animal  learns  to  perform 
a  long  series  of  movements  it  is  possible  but  not  probable 
that  anticipatory  images  of  the  next  stimulus  to  be  reacted 
to  are  formed  in  the  animal's  mind  and  aid  him  in  per- 
forming the  movements  when  the  trick  has  only  been  partly 
learned.  For  example,  where  a  monkey  or  a  raccoon  is 
to  undo  several  fastenings  in  the  same  order  he  has  pre- 

R 


242  GENETIC    PSYCHOLOGY 

viously  followed,  he  might  image  the  next  fastening,  but  at 
most  there  is  probably  nothing  more  than  an  image  of  the 
place  toward  which  he  is  next  to  turn,  as  is  often  the  case 
in  our  own  hal:>itual  acts.  It  is  not  at  all  likely  that  the 
animal  forms  a  reminiscent  image  of  what  he  did  the  other 
time  and  then  thinks,  "I  must  do  the  same  again,"  as  a 
person  sometimes  does. 

In  learning  a  series  of  manual  movements  or  in  learning 
a  selection  of  poetry,  images  of  what  one  did  before  are  in 
us  the  exception  rather  than  the  rule.  If  one  cannot  go  on 
he  is  likely  to  begin  again  the  series  and  may  then  know 
what  to  do  when  he  comes  to  the  place  at  which  he  was 
previously  obliged  to  stop.  If  he  stops  to  think  instead 
of  beginning  to  repeat  again,  he  is  likely  to  mentally  repeat 
the  first  part  of  the  series  and  may  then  think  of  the  next 
thing  to  do.  It  is  doubtful  if  animals  are  ever  able  to 
form  an  anticipatory  image  of  a  series  of  actions  to  be 
performed  so  as  to  mentally  repeat  it.  If  they  are,  that  is 
one  step  beyond  the  anticipatory  stage  in  which  images 
are  aroused  after  part  of  the  series  has  been  reproduced. 
In  other  words,  animals  rarely  or  never  have  a  train  of 
thought.  It  is  true  that  animals  do  frequently  repeat 
the  first  part  of  a  series  of  movements  when  at  any  stage 
they  are  unable  to  go  on  successfully.  This  was  an  espe- 
cially marked  feature  of  the  behavior  of  Watson's  rats, 
which  when  placed  in  the  maze  at  some  other  point  than 
at  the  usual  entrance,  if  they  could  not  at  once  find  their 
way  to  the  center  where  the  food  was,  nearly  always  went 
back  to  the  original  starting  point.  This  motor  repetition 
is  an  earlier  stage  of  development  than  that  of  mental 
repetition,  which  is  probably  possible  to  man  only. 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN     243 

Evidently  the  kind  of  associalion  formed  in  lliis  type 
of  image  formation  is  that  of  contiguity  only,  and  there 
is  not  necessarily  any  analysis  of  the  whole  situation  into 
the  elements  involved  in  the  situation  or  the  series.  In 
our  own  case  images  are  frequently  brought  to  mind  by 
concentration  of  attention  upon  some  one  element  of  what 
is  in  consciousness  until  that  brings  into  mind  an  image 
connected  with  that  element  in  some  other  situation.  In 
other  words,  images  are  brought  to  our  mind  b}- association 
of  similarity.  Images  when  thus  brought  into  mind  are  to 
some  extent  free  images  since  they  are  brought  in  by  a 
portion  of  a  new  situation  instead  of  by  a  reproduction  of 
a  group,  a  series,  or  situation  in  which  they  had  originally 
occurred.  It  is  probable  that  images  are  rarely  or  never 
brought  into  the  minds  of  animals  in  this  way  and  conse- 
quently they  have  few  if  any  free  images. 

It  is  difficult,  however,  to  distinguish  clearly  between 
images  that  are  brought  into  consciousness  by  analysis 
of  the  present  situation  and  those  that  are  brought  in  by 
the  similarity  of  the  whole  situation  or  of  the  dominant 
portion  of  it  to  the  situation  with  which  the  image  had 
been  associated  and  of  which  it  was  a  prominent  feature. 

It  is  also  sometimes  difficult  to  distinguish  between  a 
case  of  association  by  similarity  and  a  case  of  lack  of  dis- 
crimination between  two  things  that  resemble  each  other 
as  wholes  though  they  differ  in  many  respects.  Several 
experimenters  with  animals  report  tliat  animals  that  have 
been  drilled  in  undoing  fastenings  attack  entirely  new 
fastenings  by  methods  that  have  been  found  successful 
with  the  old  and  thus  usually  learn  to  undo  them  more 
quickly.     This  indicates  a  partial  analysis  of  the  situation. 


2  44  GENETIC    PSYCHOLOGY 

The  fact,  however,  that  if  the  new  fastening  demands  an 
opposite  mode  of  treatment,  the  animal  requires  a  longer 
time  than  usual  to  learn  it,  indicates  that  he  has  not  ana- 
lyzed the  situation  so  as  to  find  the  exact  points  of  simi- 
larity and  dissimilarity  as  a  person  might  do.  He  has 
perhaps  analyzed  the  case  sufficiently  to  at  once  attack 
the  fastening,  but  not  definitely  enough  to  know  in  what 
direction  to  move  it. 

Most  of  the  so-called  memories  of  animals  probably 
do  not  involve  images,  and  are  therefore  more  nearly  allied 
to  habit  reactions.  The  animal  is  readily  changed  by  an 
experience  and  may  retain  the  modification  for  a  consid- 
erable time,  so  that  when  a  portion  of  the  situation  is  re- 
produced the  appropriate  reaction  at  once  follows.  An 
animal  that  has  quickly  learned  a  trick  may  perform  it 
after  a  long  interval  when  again  confronted  with  the  proper 
situation.  This  docs  not  necessarily  imply,  however,  that 
he  has  ever  mentally  performed  the  trick  in  the  meantime ; 
nor  does  it  necessarily  imply  that  the  performance  of  other 
tricks  at  another  time  and  place  has  caused  him  to  form 
images  of  the  one  previously  learned.  Mental  images  of 
animals,  so  far  as  they  have  any,  are  evidently  closely  re- 
lated to  the  suggesting  situation  which  is  being  repeated, 
especially  to  the  movements  which  the  animal  himself  is 
to  make. 

The  fact  that  dogs  sometimes  seem  to  dream  is  not  a 
positive  proof  of  image  formation  and  memory.  It  is 
more  probable  that  the  movements  are  produced  by  sen- 
sations arising  from  the  physiological  condition  of  the 
animal  and  from  external  stimulation.  Movements  of 
various   kinds   may   be    produced    in    persons   who    are 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN     245 

asleep,  especially  habitual  ones,  such  as  turning  over  in 
response  to  a  certain  touch.  It  is  worthy  of  note  that  in 
such  cases  there  is  usually  no  memory  of  dreaming;  while 
in  most  instances  of  dreaming,  with  its  image  formation, 
there  is  no  movement,  and  if  movement  occurs,  the  dream 
usually  ceases.  This  is  additional  evidence  that  the  ap- 
paratus concerned  in  image  formation  is  different  from 
that  directly  concerned  in  performing  movements. 

Memory  usually  involves  the  production  of  images,  and 
the  process  by  which  they  are  brought  into  consciousness 
conforms  to  the  same  laws  that  govern  habitual  acts. 
When  not  only  movements  but  images  are  reproduced,  the 
term  "  memory  "  maybe  used  instead  of  that  of  "  habit." 
In  the  common  characteristic  of  retaining  and  reproducing 
former  experiences  there  is  no  difference  between  memory 
and  habit.  Memory  is  usually  the  result  of  few  repetitions, 
while  habits  are  the  result  of  many.  Habits  when  fully 
developed  involve  no  images,  while  memory  involves 
images  or  concepts. 

There  is  another  characteristic  of  memory  which  is 
probably  more  primitive  than  that  of  image  formation. 
It  is  recognition  or  a  feeling  of  familiarity.  This  feeling 
differs  somewhat  from  anticipatory  images  in  that  some 
of  the  things  leading  to  the  result  produce  a  feeling  of 
familiarity  as  they  are  experienced,  which  may  or  may 
not  be  accompanied  by  anticipatory  images.  Memory 
of  this  type  differs  but  little  from  recognition  in  perception. 
This  feeling  of  familiarity  doubtless  appears  very  early 
in  animal  life.  It  is  contrasted  with  the  feeling  of  strange- 
ness, which,  as  we  have  already  seen,  is  one  of  the  most 
common  excitants  of  fear.     Animals  probably  ha\e  this 


246  GENETIC    PSYCHOLOGY 

feeling  of  familiarity  to  as  great  an  extent  as  do  men,  but 
it  is  probably  not  accompanied  in  their  consciousness,  as 
it  often  is  in  ours,  by  the  thought  that  the  object  has  been 
experienced  before.  Recognition  may  occur  for  things 
that  have  been  perceived  once  or  many  times,  and  one's 
attitude  toward  the  object  may  persist  without  definite 
intellectual  accompaniments.  For  example,  the  writer 
once  recognized  a  face  in  an  audience  as  familiar,  was  sure 
that  the  person  had  been  well  known  to  him  and  was  re- 
garded in  a  friendly  but  not  wholly  trustful  way,  but  was 
unable  to  recollect  any  one  definite  thing  regarding  the 
person  until  afterward,  when  he  met  him  and  heard  his 
name.  Recognition  in  the  form  of  persistence  in  an  atti- 
tude toward  a  person  or  thing  is  doubtless  a  prominent 
feature  of  animal  memory,  which  the  many  stories  of  ele- 
phants and  other  creatures  revenging  themselves  upon 
persons  who  have  injured  them  years  before,  illustrate. 

In  human  psychology  a  mental  process  is  not  supposed 
to  be  a  memory  unless  it  is  not  only  reproduced  but  is 
known  as  a  former  mental  state  that  can  be  contrasted 
with  the  present  one.  This  kind  of  memory  probably 
involves  not  only  consciousness  but  self-consciousness. 
Only  when  this  kind  of  memory  is  possible  are  there 
produced  what  may  be  called  reminiscent  images,  in  the 
production  of  which  one  does  not  entirely  lose  conscious- 
ness of  the  present  but  has  a  feeling  of  contrast  between 
the  past  and  the  present  circumstances.  There  is  no 
good  reason  for  believing  that  any  animal  possesses  mem- 
ory in  this,  its  true  form. 

Another  element  in  memory  of  great  importance  in  man 
is  that  of  location  of  the  reproduced  experience  as  having 


J 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN    247 

occurred  at  a  certain  time  or  place  or  in  connection  with 
certain  other  experiences  of  one's  own.  This  kind  of 
memory  implies  the  existence  of  free  images  and  a  further 
consciousness  of  the  relation  of  images  to  each  other. 
Hence  memory  in  this  sense  is  probably  not  found  in 
animals. 

Concepts  and  Reasoning 

Since  concepts  represent  a  higher  stage  of  psychical 
development  than  free  images,  and  since  we  have  already 
decided  that  animals  can  have  very  few  free  images,  it  at 
once  follows  that  we  conclude  that  they  have  no  concepts. 
It  is  worth  while,  however,  to  devote  a  few  paragraphs  to 
the  consideration  of  behavior  which  has  been  supposed 
to  indicate  that  animals  have  concepts  or  general  ideas, 
or  at  least  what  Romanes  calls  "recepts." 

There  is  no  question  whatever  that  animals  do  react  to 
classes  of  objects  in  ways  as  definitely  fitting  as  they  do  to 
individual  objects.  Each  species  of  animals  reacts  to  the 
enemies  of  its  species  and  to  classes  of  food  suitable  to  it. 
Birds  react  to  liquids,  when  alighting,  in  a  different  way 
from  what  they  do  to  solids.  This  has  been  supposed  by 
Romanes  to  indicate  the  existence  of  general  ideas  of  each 
group  of  objects  as  a  class.  The  term  "  instinctive  per- 
cepts "  is  doubtless  however  a  better  name  to  apply  to  the 
mental  state  involved  in  the  action.  There  is  no  reason  to 
suppose  that  the  mental  state  arises  except  when  a  sensory 
stimulus  is  received  and  a  reaction  is  to  be  made.  In  many 
cases  a  reaction  to  the  members  of  a  class  does  not  diflfer 
from  the  reactions  to  an  individual  of  the  class  simply 
because  there  is  no  discrimination  of  the  finer  differences 


248  GENETIC    PSYCHOLOGY 

between  individuals,  but  only  of  those  that  distinguish  one 
class  from  another. 

In  cases  of  acquired  modes  of  reaction  to  a  class  of  ob- 
jects, as,  for  example,  the  avoidance  of  all  men  by  birds, 
the  mental  state  is  probably  better  described  by  the  term 
"acquired  perception"  than  by  the  word  "concept."  If 
an  individual  bird  has  learned  to  respond  to  one  specific 
individual  in  a  different  manner  from  that  used  to  other 
members  of  the  class,  we  have  simply  an  instance  of  an 
acquired  perception  more  definite  in  its  character  than 
that  indicated  by  the  reaction  to  the  members  of  a  group. 
In  this,  as  in  the  other  case,  the  mental  state  is  probably 
never  aroused  except  by  sensory  stimulation. 

Reasoning,  in  the  sense  of  responding  to  a  situation  in  a 
way  that  has  previously  brought  satisfactory  results,  is 
shown  by  animals  as  well  as  by  man ;  but  reasoning  in  the 
sense  of  analyzing  a  situation,  and  identifying  the  element 
upon  which  results  depend,  is  probably  never  shown.  Most 
untrained  persons  do  much  of  their  reasoning  from  particu- 
lar to  particular  without  consciously  starting  or  ending  with 
a  clearly  represented  general  truth,  and  the  same  is  true 
of  a  good  deal  of  the  reasoning  of  many  cultured  people. 
The  so-called  "reasoning"  of  animals  is  somewhat  similar 
to  this  kind  of  reasoning  in  man,  the  chief  difference  being 
that  similarity  of  the  situation  as  a  whole  to  a  previous 
situation  is  to  a  greater  extent  the  basis  of  reasoning  in 
animals,  while  in  man  it  is  not  only  the  situation  as  a  whole 
but  specific  things  or  characteristics  in  that  situation  that 
are  made  the  basis  of  the  inferences. 

In  both  men  and  animals  the  most  fundamental  basis 
of  all  reasoning  is  found  in  the  general  law  of  habit,  which 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN     249 

produces  a  tendency  to  do  the  same  thing  under  the  same 
circumstances,  that  is  strong  in  proportion  as  the  situation 
and  act  have  been  repeated  many  times,  recently  and  with 
intensity.  Where  the  situation  and  the  act  arc  exactly 
the  same,  we  speak  of  any  particular  performance  as  an 
habitual  act.  When  there  are  many  new  elements  in  the 
situation  and  in  the  act,  and  when  some  specific  element 
in  the  situation  is  met  by  a  mode  of  action  that  has  never 
previously  been  associated  with  the  present  situation,  the 
act  is  usually  supposed  to  indicate  reasoning. 

Much  of  the  discussion  regarding  the  possibility  of 
animals  reasoning  is  meaningless  because  of  differing 
conceptions  of  what  constitutes  reasoning.  There  are 
many  instances  of  animal  and  human  behavior  that  on  the 
surface  look  like  reasoning,  in  the  sense  that  a  situation  only 
partly  like  one  previously  met  is  reacted  to  in  the  way  that 
previously  brought  favorable  results.  The  stricter  psy- 
chological definition  of  reasoning,  however,  demands  that 
the  situations  shall  have  been  analyzed  and  a  free  idea  of 
its  essential  element  compared  with  an  abstract  general 
truth  regarding  such  element  and  situation.  Our  previous 
study  has  shown  that  free  ideas  are  rarely  or  never  pos- 
sessed by  animals,  and  that  abstract  ideas  are  utterly  im- 
possible to  them.  It  follows,  therefore,  that  they  cannot 
reason  in  the  stricter  meaning  of  the  word  "reason." 

That  animals  and  persons  who  can  do  little  or  no  reason- 
ing, in  the  strict  meaning  of  the  word,  can  profit  by  former 
experience  when  they  meet  situations  that  are  partly  new, 
cannot  be  doubted.  In  the  case  of  animals  this  can  only 
be  done  when  their  senses  are  actually  being  affected,  while 
in  human  beings  it  may  be  done  by  means  of  images  of 


250  GENETIC    PSYCHOLOGY 

concrete  situations.  The  real  difference  between  reason- 
ing and  other  processes  that  accomplish  similar  results 
is  much  the  same  as  is  recognized  in  general  psychology 
in  distinguishing  thinking  from  perception  and  imagina- 
tion, and  as  is  emphasized  in  a  subsequent  chapter  in  dis- 
tinguishing the  conceptual  from  the  representative  and 
sensory  motor  types  of  intelligence. 

VOLITIONAL   ACTIVITY 

Interest  and  attention  are  objectively  indicated  when  one 
stimulus  appears  to  dominate  the  activity  of  an  animal 
in  spite  of  other  stimuli  that  are  being  received.  Even  as 
low  a  creature  as  the  Paramecium  may,  when  feeding, 
fail  to  react  to  rather  intense  stimulations  of  heat  or  light 
that  would  ordinarily  produce  marked  reactions.  When 
there  is  any  consciousness  accompanying  this  objective 
attitude  of  interest  and  attention  it  is  doubtless  concerned 
"wholly  with  the  dominant  stimulus  and  the  reaction  being 
made  to  it.  In  such  cases  as  this,  however,  where  the 
stimulus  is  itself  immediately  favorable  or  unfavorable, 
it  is  very  doubtful  whether  there  is  any  mental  state  ac- 
companying the  act. 

Where  the  stimulus  dominating  activity  is  suggestive 
rather  than  immediate,  as  when  a  cat  is  watching  and 
creeping  toward  a  bird,  it  is  probable  that  there  is  a  con- 
scious state  accompanying  the  attitude  and  that  this  con- 
scious state  consists  largely  of  a  feeling  of  attraction  and 
expectation  and  a  more  or  less  definite  anticipatory  image 
of  the  result  to  be  obtained. 

Attention    to    immediate    stimuli    is    probably    always 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN     25 1 

reflex  or  instinctive,  while  that  to  suggestive  stimuli  may 
be  either  instinctive  or  acquired.  Interest  is  instinctive 
in  the  sense  that  the  creature  is  so  organized  that  certain 
kinds  of  stimuli  tend  to  dominate  his  activity  even  though 
others  of  equal  or  greater  intensity  are  being  received  at 
the  same  time.  The  structure  and  conditions  of  life  of 
each  species  have  made  it  necessary  that  they  should  be 
more  sensitive  to  some  kinds  of  stimuli  than  to  others. 
For  example,  a  small  moving  object  of  any  kind  is  an 
especially  strong  stimulus  to  a  cat,  and  for  the  time  being 
is  likely  to  completely  dominate  his  behavior.  Chickens 
have  an  instinctive  interest  in  objects  moving  swiftly  over 
them,  while  they  have  an  acquired  interest  in  the  move- 
ments of  persons  who  have  frequently  brought  them  food. 
In  general,  both  instinctive  and  acquired  interest  are  more 
or  less  closely  connected,  either  with  the  immediate  satis- 
faction of  needs  or  with  things  that  are  means  to  the  satis- 
faction of  some  instinctive  need.  In  animals,  therefore, 
interest  and  attention  are  connected  almost  exclusively 
with  the  satisfaction  of  biological  needs,  while  in  man, 
interest  in  the  satisfaction  of  mental  needs  plays  a  large 
part. 

On  the  mental  side  the  most  elementary  ])henomenon 
of  interest  probably  consists  in  a  mere  feeling  of  attraction. 
In  a  higher  stage  of  development  there  is  a  vague  antici- 
patory image  of  the  general  character  of  the  result  to  be 
experienced.  In  a  still  higher  stage  of  development  there 
is  a  more  definite  anticipatory  image  of  the  result  and 
some  images  of  what  will  lead  to  it.  The  higher  animals 
may  have  some  interest  of  this  sort,  though  representa- 
tions of  just  what  leads  to  the  result  are  probably  few 


252  GENETIC    PSYCHOLOGY 

and  transient,  even  when  the  suggesting  object  or  antece- 
dent stimulus  is  present. 

In  man  the  exact  result  to  be  obtained  and  the  elements 
leading  to  that  result  may  be  represented  with  a  great 
deal  of  definiteness,  and  memory  images  may  be  formed 
of  parts  of  a  number  of  experiences,  and  related  to  each 
other  in  such  a  way  as  to  bring  about  the  desired  result 
in  the  present  situation.  Such  a  mental  state  is  by  no 
means  universal  in  the  attentive  activity  of  man.  Much 
of  our  attention  is  not  accompanied  by  these  conscious 
states,  although  the  fact  that  when  observed  they  are 
prominent  features  of  consciousness  is  likely  to  lead  us 
to  think  that  they  are  always  so.  Such  attention  as  this 
evidently  involves  association  of  similarity  and  numerous 
free  images  and  ideas.  Hence  attention  in  this  sense 
is  almost  if  not  wholly  impossible  for  animals. 

Animals  usually  respond  almost  immediately  to  the 
stimulus  that,  because  of  its  objective  strength  or  because 
of  the  instinctive  or  acquired  tendency  in  the  animal,  is 
at  the  time  the  strongest.  There  is  therefore  no  oppor- 
tunity for  deliberation  and  formation  of  images  of  other 
acts  that  might  be  performed  or  results  obtained  under 
the  present  circumstances.  Occasionally,  animals  do 
pause  for  a  moment  under  the  influence  of  two  stimuli, 
either  of  which  if  received  alone  would  immediately  dom- 
inate action.  For  example,  a  dog  that  is  chasing  some 
hogs  may  stop  when  he  hears  his  master's  call,  and  for  a 
while  it  is  uncertain  as  to  whether  he  will  continue  chasing 
the  hogs  or  return  to  his  master.  Such  a  pause  might  be 
supposed  to  be  occupied  with  the  formation  of  images  of 
the  results  of  the  two  courses  of  action,  but  it  is  probable 


SPECIFIC  CONSCIOUS  STATES  OF  ANIMALS  AND  MAN     253 

that  such  imagery  is  almost  if  not  wholly  lacking.  That 
the  action  of  the  animal  is  dominated  by  sensory  stimuli 
rather  than  by  images,  is  indicated  by  the  fact  that  the 
pause  is  readily  converted  into  vigorous  action  in  one  di- 
rection or  the  other  by  a  supplementary  stimulus,  such 
as  the  passing  of  a  hog  near  the  dog,  or  a  louder  call  from 
the  master. 

In  some  instances,  however,  when  there  is  no  ])rominent 
external  stimulus  perce])tible  to  man,  a  dog  will  stand  as 
if  considering  what  to  do  and  then  go  and  do  something. 
In  such  cases  there  may  be  a  sensory  stimulus  uni)er- 
ceived  by  the  human  observer  that  directs  the  action  of 
the  animal,  but  it  is  also  possible  that  in  some  instances 
imagery  of  some  kind  may  play  a  part  in  initiating  and 
directing  the  activity  of  the  animal.  It  is  probably  true 
that  in  many  instances  the  physiological  condition  of 
the  animal,  as  for  example  a  state  of  hunger,  initiates 
the  action.  Perhaps  there  is  an  anticipatory  image  of  the 
place  or  direction  in  which  to  go  to  find  satisfaction  of  the 
physiological  need,  but  the  more  specific  direction  of  move- 
ments is  later  determined  by  the  stimuli  that  are  received 
as  the  animal  moves  from  place  to  place.  An  animal 
may  thus  go  where  he  has  previously  hunted,  but  the  actual 
hunting  is  probably  directed,  not  by  images,  but  by  sensory 
stimulations  as  they  come  to  him. 

Instinct  and  habit,  rather  than  memory,  usually  if  not  al- 
ways direct  the  action  of  even  the  higher  animals.  A  dog 
when  hungry  will  go  to  the  place  where  he  has  previously 
found  food,  but  he  may  sec  food  placed  in  a  new  position 
and  show  no  evidence  of  any  consciousness  of  it  afterward 
unless  his  senses  are  actuallv  affected  bv  it.     This  was 


254  GENETIC   PSYCHOLOGY 

clearly  shown  by  experiments  upon  a  very  clever  dog  that 
was  very  fond  of  candy.  When  the  word  "candy"  was 
spoken  he  would  go  to  places  where  he  had  previously 
obtained  candy;  but  if  a  piece  of  candy  were  given  him 
from  a  bag  and  the  bag  placed  on  a  chair,  the  word  "  candy," 
uttered  a  few  minutes  later,  would  not  cause  him  to  go  to 
the  bag  but  to  the  usual  place  where  candy  had  been 
found. 

From  the  above,  it  is  clear  that  if  representation  of  more 
than  one  end  or  of  more  than  one  means  of  obtaining  an 
end  is  necessary  to  an  act  of  will,  then  animals  can  show 
very  little  if  any  volitional  activity.  They  may  persist  in 
trying  to  reach  an  end,  and  in  doing  so  use  various  means ; 
but  the  means  to  be  used  are  usually  suggested  by  the 
stimulating  conditions  and  the  previous  habits  of  the 
animal  rather  than  by  specific  images  and  memories.  It 
is  true  that  the  actions  of  human  beings,  especially  of 
children,  are  directed  in  a  similar  manner;  but  it  is  also 
true  that  in  their  minds  specific  images  are  likely  to  play 
some  part  in  all  deliberative  action,  and  in  many  instances 
images  and  ideas  play  the  whole  part  at  the  time,  the 
movements  corresponding  to  the  decision  being  made 
only  after  a  long  interval. 

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CHAPTER   IX 
TYPES   OF   ADAPTIVE   ACTIVITY   OR   INTELLIGENCE 

A    BROADER    CONCEPTION    OF    INTELLIGENCE 

The  word  "intelligence  "always  implies  the  adaptation  of 
means  to  ends,  but  it  has  usually  been  limited  to  conscious 
processes.  In  order  that  psychology,  physiology,  and 
biology  may  find  a  common  ground  for  the  consideration 
of  behavior  it  is  necessary  that  either  the  term  "  intelligence" 
shall  be  given  a  broader  meaning,  some  differentiating  term 
like  "  adaptation  "  be  used,  or  some  new  term  invented 
to  indicate  the  most  prominent  characteristic  of  all  organs 
and  organisms,  i.e.  that  of  activity  suited  to  self-preserva- 
tion. The  word  "Organoses"  would  be  a  good  word  to 
indicate  organic  activity,  whether  conscious  or  unconscious, 
including  the  original  meanings  of  the  two  terms  "  neuroses  " 
and  "psychoses."  The  author  for  present  purposes,  how- 
ever, prefers  to  extend  the  meaning  of  the  word  "  intelli- 
gence "  so  as  to  include  unconscious  as  well  as  conscious 
activities  that  are  suited  to  the  preservation  of  organic  unity. 

Having  recognized  the  common  characteristic  of  all 
organic  activity,  it  will  be  possible  to  classify  activities 
according  to  the  way  in  which  they  secure  the  preservation 
of  the  organisms.  Our  previous  study  of  behavior  has 
shown  that  the  difference  between  actions  of  lower  and 
higher  animals  is  not  in  the  end  gained  but  in  the  mode 
of  activity  by  which  it  is  gained.  Plants  gain  the  end  of 
s  257 


258  GENETIC    PSYCHOLOGY 

preservation  chiefly  by  means  of  slow  growth  activities, 
while  animals  use  to  a  considerable  extent  organs  of  move- 
ment in  preserving  life.  Higher  animals  store  up  in  their 
systems  the  results  of  activity  in  such  a  way  as  to  be  helpful 
in  future  preservative  acts,  and  if  acts  are  varied  and 
complex  and  must  be  quickly  modified  to  meet  changing 
conditions,  as  is  the  case  in  man,  consciousness  plays  an 
important  part.  All  of  these  kinds  of  activity  are  intelligent 
in  a  high  degree  in  the  sense  of  adapting  means  to  ends. 
The  differences  viewed  objectively  consist  chiefly  in  the 
number  of  adaptations  and  the  quickness  and  accuracy 
with  which  they  are  made  and  modified. 

By  thus  extending  the  meaning  of  the  word  "  intelli- 
gence" the  truths  of  several  sciences  may  be  brought  into 
intimate  relation  and  their  significance  better  appreciated. 
In  thus  classifying  the  various  types  of  intelligence,  famil- 
iar psychological  classifications  may  be  used  and  shown 
to  have  a  more  fundamental  basis  than  has  usually  been 
supposed.  It  has  long  been  recognized  that  physiological 
processes  have  important  influences  upon  mental  processes, 
determining  whether  conscious  processes  shall  or  shall  not 
be  intelligent  in  the  sense  of  being  w^ell  adapted  to  the  se- 
curing of  ends.  In  the  treatment  here  proposed,  physio- 
logical activity,  instead  of  being  regarded  simply  as  injlu- 
encing  mental  activity,  will  be  considered  as  one  type  of 
intelligence.  The  other  types  of  intelligence  will  corre- 
spond quite  closely  with  the  old  division  of  intelligence  into 
presentative,  representative,  and  thinking  processes.  The 
term  "sensory  motor"  intelligence  will  be  used  for  the  first, 
"  representative  "  for  the  second,  and  "  conceptual  "  for 
the  third. 


TYPES  OF  ADAPTIVE  ACTIVITY   OR   INTELLIGENCE     259 

In  our  study  of  typical  forms  of  behavior  wc  found  that 
the  dominant  form  of  intelligence  in  the  lower  organisms  is 
physiological,  while  in  those  a  little  higher  sensory  motor 
intelligence  becomes  prominent.  In  the  higher  species 
of  animals  there  is  perhaps  a  slight  development  of  rep- 
resentative intelligence,  while  in  man  this  form  of  intelli- 
gence is  very  prominent  and  is  supplemented  by  concep- 
tual intelligence. 

In  our  study  of  the  structural  basis  of  behavior  we  found 
that  the  lowest  organisms  were  without  nervous  tissue, 
and  that  the  nervous  system  became  a  more  prominent  ele- 
ment of  the  organism  as  we  went  upward  in  the  scale  of 
animal  life.  We  found  that  in  man  there  is  a  nervous 
apparatus  at  different  levels,  concerned  in  different  kinds 
of  behavior  similar  to  those  of  the  lower  animals,  and  in 
addition  certain  apparatus  in  the  cerebrum,  either  not  pos- 
sessed or  possessed  only  in  a  slight  degree  by  any  other 
creature  than  man. 

With  such  conceptions  and  classifications  it  will  be  much 
easier  to  correlate  the  truths  of  physiology  and  psychology, 
to  compare  the  behavior  of  lower  animals  with  that  of  the 
higher  and  with  that  of  human  beings,  and  to  trace  the  de- 
velopment of  behavior  and  ideas  in  individuals. 

PHYSIOLOGICAL   INTELLIGENCE 

Physiological  intelligence  is  shown  especially  in  nutritive 
and  growth  processes.  At  first  thought  it  seems  incon- 
gruous to  speak  of  physiological  processes  as  intelligent. 
When,  however,  wc  view  intelligence  in  an  entirely  objec- 
tive way  as  the  adaptation  of  means  to  ends,  v;c  find  good 


26o  GENETIC   PSYCHOLOGY 

reason  for  looking  upon  physiological  processes  as  highly 
intelligent. 

As  a  builder,  physiological  intelligence  is  not  surpassed 
by  the  greatest  mechanic  or  architect.  A  tree  with  its 
beauty  and  strength  may  well  compare  with  any  structure 
planned  by  an  architect,  and  the  human  body  as  a  machine 
is  far  suj)erior  to  any  as  yet  constructed  by  man.  The 
engineer  who  tears  down  an  old  bridge  and  erects  a  new 
one  while  trains  are  running  over  it,  has  performed  a 
remarkable  feat,  but  not  so  great  as  that  performed  by 
physiological  intelligence  in  directing  the  processes  of 
growth  in  which  a  large  number  of  complex  organs  are 
torn  down,  built  up,  and  increased  in  size  without  any 
interference  whatever  with  their  activities  or  the  harmony 
of  their  working.  Discriminative  and  selective  activity, 
which  chooses  from  the  various  substances  introduced  into 
the  body  just  the  right  elements  for  the  building  of  each 
organ,  is  certainly  comparable  in  accuracy  to  the  perceptive 
judgment  of  the  human  builder. 

The  physiological  processes  by  which  life  and  health  are 
maintained  are  comparable,  in  the  complexity  of  activities 
that  must  be  related  and  harmonized,  to  the  most  complex 
machine  constructed  by  man  and  even  to  the  activities 
unified  in  consciousness.  To  give  a  single  illustration,  no 
heat-regulating  device  as  yet  invented  by  man  will  keep  a 
building  at  a  temperature  so  nearly  uniform,  amid  rapidly 
changing  external  conditions,  as  is  the  temperature  of  the 
body,  maintained  by  physiological  intelligence.  So  per- 
fectly does  it  perform  this  function  that  a  variation  of  only 
a  few  degrees  in  the  temperature  of  the  body  indicates  a 
serious  derangement  in  the  physiological  activities. 


TYPES  OF  ADAPTIVE  ACTIVITY  OR   INTELLIGENCE     261 

Physiological  processes,  as  well  as  other  forms  of  intelli- 
gent acti\'ity,  are  subject  to  modljlcation  by  experience. 
The  physiological  j)rocesses  correspond  to  the  food,  exer- 
cise, and  climate  usual  to  tlie  indixidual,  but  they  (juickly 
adjust  themselves  to  changes  in  any  or  all  of  these  respects, 
although  such  adjustment  probably  involves  a  modification 
of  the  activity  of  nearly  every  gland  and  organ  in  the  body. 
The  organism  may  become  habituated  to  the  use  of  drugs 
to  such  an  extent  that  a  dose  that  would  produce  instant 
death  in  one  unhabituated  to  their  use  will  have  but  little 
effect. 

Not  only  may  the  physiological  processes  be  passively 
habituated  to  new  conditions  and  substances,  but  what 
correspond  to  active  habits  may  be  formed.  In  some 
instances,  instead  of  becoming  accommodated  to  certain 
drugs  or  conditions,  there  is  increased  sensitiveness,  so 
that  smaller  quantities  will  produce  greater  effects  in  an 
individual  who  has  prcNiously  taken  the  poison  or  the 
food  in  excess  than  would  be  produced  upon  an  individ- 
ual that  had  never  had  such  experience.  This  is  quite 
analogous  to  growth  in  sensitiveness  and  discrimination 
by  the  senses. 

In  such  cases  as  this,  and  also  in  cases  of  disease,  single 
experiences  may  produce  permanent  effects  similar  to 
those  in  conscious  memory.  A  single  attack  of  certain 
diseases,  such  as  measles,  usually  renders  the  individual 
forever  immune  to  further  attacks,  just  as  if  the  experi- 
ence were  remembered  and  avoided.  In  the  case  of  other 
diseases  a  single  attack  renders  one  ever  after  more  sus- 
ceptible to  the  disease,  e.g.  pneumonia. 

When  subjected   to   unfavorable   conditions,  the   vital 


262  GENETIC    PSYCHOLOGY 

organs  modify  their  activity  until  relief  is  obtained  in 
ways  that  arc  analogous  to  the  behavior  of  the  stentor 
under  continued  unfavorable  stimulation.  It  is  probable 
that  in  reacting  to  new  situations  the  various  organs  and 
glands  not  only  have  fixed  reflex-like  modes  of  reaction, 
but  that  they  vary  their  activity  in  a  way  analogous  to  that 
of  trial  movement.  However  this  may  be,  we  know  that 
a  change  in  the  activity  of  any  organ  or  gland  is  met  by 
corresponding  changes  in  every  other  part  of  the  body, 
especially  in  those  parts  whose  function  is  most  intimately 
associated  with  the  one  first  affected,  e.g.  change  in  lung 
activity  affects  also  the  organs  of  circulation  and  nutrition. 
The  complexity  of  correlation  thus  involved  is  quite  com- 
parable to  that  revealed  in  the  relation  of  conscious  states 
to  each  other. 

We  see,  therefore,  that  the  phenomenon  of  physiological 
intelligence  is  very  similar  to  that  of  conscious  intelligence. 
The  difference  is  not  so  much  in  the  complexity  of  the 
activities  related  and  unified  in  the  accomplishment  of 
an  end  as  in  the  rapidity  with  which  it  is  done.  Where 
a  physiological  process  requires  hours  or  years,  the  con- 
scious process  may  only  require  seconds  or  minutes.  For 
example,  the  various  qualities  of  an  article  of  food  may  be 
consciously  discriminated  in  a  few  seconds  and  some  of  the 
elements  combined  to  form  a  new  concept  in  a  few  minutes, 
while  the  physiological  process  of  separating  the  particles 
of  food  and  building  them  up  into  the  tissues  of  the  body 
would  require  hours  and  days. 

The  physiological  processes  are  worthy  of  study,  not  only 
in  themselves,  as  instances  of  a  high  degree  of  objective 
intelligence,  but  because  other  forms  of  intelligence  are 


TYPES  OF  ADAPTIVE  ACTIVITY   OR   INTELLIGENCE    263 

dependent  upon  the  perfect  working  of  apparatus  that  is 
built  up  and  kept  in  working  order  by  means  of  physiologi- 
cal processes.  The  circulatory,  respiratory,  and  digestive 
organs,  together  with  the  sympathetic  nervous  system, 
constitute  the  apparatus  especially  concerned  in  physio- 
logical activities.  The  other  portions  of  the  nervous  sys- 
tem that  are  especially  concerned  in  other  forms  of  intelli- 
gent activity  are  perfected  and  kept  in  good  working  order 
by  means  of  the  physiological  activities.  The  physio- 
logical apparatus  bears  much  the  same  relation  to  the  rest 
of  the  body  that  the  heating  and  power  plant  bears  to 
the  various  machines  in  a  manufacturing  establishment. 
The  relation  is  more  close,  however,  for  not  only  is  power 
furnished  each  apparatus  in  the  human  body,  but  it  is  kept 
in  repair  and  in  good  working  condition  by  the  physio- 
logical intelligence.  The  special  physiological  activity  in- 
volved in  the  functioning  of  the  higher  nerve  centers  must 
be  exceedingly  delicate  and  rapid  to  make  possible  the 
precise  and  lightning-like  activity  of  conscious  processes. 
In  tracing  the  development  from  the  lower  forms  upward 
we  note  that  the  chief  type  of  intelligence  manifested  by 
the  lower  animals  is  physiological ;  yet  the  apparatus  con- 
cerned in  maintaining  the  life  processes  becomes  more 
and  more  complex.  The  evolution  of  organs  concerned 
in  the  higher  types  of  intelligence  does  not  greatly  surpass 
in  complexity  that  shown  in  the  differentiation  of  vital 
organs,  by  means  of  which  physiological  intelligence  is 
manifested  in  the  higher  animals  and  in  man.  In  other 
words,  there  has  been  almost  as  much  increase  in  physio- 
logical intelligence,  from  the  lowest  animals  to  man,  as 
there  has  been  in  the  higher  forms  of  conscious  intelligence. 


264  GENETIC   PSYCHOLOGY 

SENSORY   MOTOR   INTELLIGENCE 

While  physiological  intelligence  is  concerned  with  the 
direction  of  activities  taking  place  within  the  body  in  such 
a  way  as  to  preserve  life,  the  sensory  motor  intelligence  is 
concerned  with  directing  movements  of  a  part  or  all  of 
the  body  in  response  to  external  stimulation  in  such  a  way 
that  favorable  results  may  be  secured.  All  immediate 
responses  to  sensory  stimulation,  such  as  reflexes  and  per- 
ceptions, are  under  the  direction  of  sensory  motor  intelli- 
gence. Plants  and  some  forms  of  animals  that  remain 
constantly  fixed  in  the  same  environment  and  subjected 
to  the  same  influences,  are  able  to  preserve  life  by  means 
of  the  slower  growth  processes  of  physiological  intelli- 
gence. Creatures  that  move,  however,  are  constantly 
being  subjected  to  new  stimulations,  which  must  be  re- 
sponded to  in  order  that  life  may  be  successfully  main- 
tained. Hence  a  high  degree  of  development  of  the  sen- 
sory motor  intelligence,  by  means  of  which  fitting  reactions 
may  be  made,  is  of  great  advantage  in  the  struggle  for 
existence. 

Sensory  motor  intelligence  is  manifested  to  some  extent 
by  creatures  not  possessing  a  distinct  nervous  and  muscular 
system,  but  is  much  more  prominent  in  creatures  thus  en- 
dowed. In  its  simplest  form  this  kind  of  intelligence  is 
shown  in  comparatively  uniform  reflex  movement  in  re- 
sponse to  stimulation  and  in  trial  movements.  It  is  best 
manifested,  not  so  much  in  single  reflex  movements,  as 
in  a  series  or  combination  of  such  movements  that  are  so 
related  to  each  other  that  they  all  contribute  to  the  same 
end.     This  is  shown  in  a  remarkable  way  in  instinctive 


TYPES  OF  ADAPTIVE  ACTIVITY  OR   INTELLIGENCE    265 

reactions  of  all  kinds,  especially  in  those  made  in  response 
to  suggestive  stimuli  and  in  proj)er  correlation  with  the 
physiological  condition  of  the  animal  at  the  time.  Sen- 
sory motor  intelligence  may  be  regarded  as  greatest  in 
acquired  reactions  to  complex  and  varied  situations  and 
in  perceptual  activity  of  all  kinds.  It  is  manifested  in  a 
high  degree  in  all  forms  of  manual  work  and  athletics. 

The  apparatus  concerned  in  sensory  njotor  intelligence 
in  the  higher  animal  consists  (i)  of  specialized  nerve  end- 
ings, (2)  muscles,  (3)  nerve  fibers,  and  (4)  a  nerve  center. 
This  is  the  apparatus  used  in  the  simplest  form  of  reflex 
action.  In  more  complex  forms  of  instinctive  and  percep- 
tual reaction  several  sense  organs,  thousands  of  nerve  fibers, 
a  number  of  nerve  centers,  and  many  muscles  act  together 
in  a  unified  way  so  as  to  accomplish  a  definite  result. 

In  order  that  there  may  be  a  high  degree  of  sensory 
motor  intelligence  manifested,  there  must  be  not  only  highly 
specialized  sense  organs,  many  muscles,  nerve  fibers,  and 
nerve  centers,  but  they  must  all  be  related  to  each  other 
in  such  a  way  that  there  is  a  proper  balance  or  equilibrium 
of  activity,  and  so  that  all  may  act  together  harmoniously 
in  the  accomplishment  of  an  end.  Any  over-development 
of  any  portion  of  a  complex  and  closely  related  sensory 
motor  apparatus  will  give  that  part  undue  prominence  in 
determining  the  direction  of  activity,  while  any  lack  of 
perfect  connection  between  the  parts  or  in  the  various  ad- 
justments for  meeting  changing  situations  will  interfere 
with  the  successful  attainment  of  ends,  e.g.  cross  eyes 
may  result  from  o\'er-action  of  one  of  two  opposing  muscles, 
with  the  result  that  the  two  images  are  not  properly  com- 
bined and  vision  is  poor. 


266  GENETIC    PSYCHOLOGY 

Although  considerable  changes  in  the  character  of  sen- 
sory motor  reactions  may  be  produced  by  decrease  or 
increase  in  the  perfectncss  of  the  peripheral  organs  of 
sensation  and  motion,  yet  the  most  important  modifica- 
tions in  activity  are  produced  by  changes  in  the  nerve  cen- 
ters and  their  connections.  These  are  the  parts  also  most 
readily  changed  by  exercise,  a  single  unfavorable  or  favor- 
able experience  often  producing  marked  changes  in  sub- 
sequent activity;  e.g.  the  sight  of  medicine  after  a  single 
experience  may  produce  nausea.  The  connections  be- 
tween centers  become  more  or  less  close  according  as 
impulses  passing  between  them  have  had  favorable  or  un- 
favorable results.  The  close  connection  between  all  parts 
of  the  nervous  system  and  the  readiness  with  which  even 
the  most  elementary  reflex-like  actions  are  modified  by 
experience  so  that  they  can  be  called  into  action  by  impulses 
from  other  centers,  are  well  illustrated  by  experiments  up- 
on the  tendon  reflex  or  knee  jerk.  Stratton,  who  had  been 
carrying  on  such  experiments  for  some  time,  accidentally 
discovered  that  the  mechanism  concerned  had  learned  to 
respond  to  a  suggestive  stimulus.  In  the  apparatus  used 
a  sound  w^as  always  made  just  before  the  tendon  was  struck, 
and  after  a  great  many  experiments  had  been  made,  the 
apparatus  failed  to  work  properly,  so  that  the  sound  was 
made  but  the  tendon  was  not  struck;  yet,  much  to  his  sur- 
prise, the  reaction  was  the  same  as  if  the  tendon  had  been 
directly  stimulated.  Since  the  reflex  is  involuntary  and 
without  conscious  direction,  it  must  be  that  the  change  in 
reaction  so  that  the  movement  is  made  in  response  to  an 
associated  stimulus  is  a  case  of  unconscious  learning  by 
the  sensory  motor  apparatus. 


I 


TYPES  OF  ADAPTIVE  ACTIVITY  OR  INTELLIGENCE     267 

The  sensory  motor  intelligence  becomes  greater,  not 
only  in  proportion  to  the  number,  variety,  complexity, 
and  unity  of  action  of  the  mechanisms  concerned,  but  in 
proportion  to  the  readiness  with  which  the  apparatus  is 
modified  by  experience.  Since  the  modification  depends 
largely  upon  changes  in  the  nerve  centers,  an  increase  in 
the  number  of  ner\e  centers  connected  with  the  sensory 
motor  apparatus  would  naturally  increase  the  number  and 
rapidity  of  modifications  in  activity.  In  the  higher  ani- 
mals and  in  man  there  is,  therefore,  a  high  degree  of  sen- 
sory motor  intelligence.  For  example,  the  sensory  motor 
mechanism  by  means  of  which  a  man  catches  a  flying 
ball,  or  a  swallow  a  flying  insect,  is  more  perfectly 
adapted  for  the  purpose  than  any  machine  constructed 
by  man. 

In  animals  the  proper  connection  between  parts,  in  order 
that  successful  reactions  may  be  made  to  the  various 
situations  likely  to  be  met  with,  is  partly  developed  at 
birth,  while  in  man  it  is  to  a  greater  extent  acquired  by 
experience.  The  sensory  motor  intelligence  of  the  bee,  by 
means  of  which  it  constructs  its  comb  in  such  a  way  as 
to  secure  the  greatest  strength  with  the  smallest  amount 
of  material,  is,  in  its  success  in  securing  an  end,  quite  com- 
parable to  the  calculation  of  the  engineer.  The  bee  suc- 
ceeds in  doing  this  because  his  sensory  motor  apparatus 
is  constructed  and  adjusted  in  such  a  way  as  to  produce 
this  definite  result.  The  hawk  in  swooping  upon  his  prey 
takes  a  course  which,  according  to  mechanical  principles, 
is  known  to  be  most  favorable  for  securing  success.  In  this 
case  success  depends  not  so  much  upon  the  structure  of 
the  apparatus  as  upon  the  rapid  making  of  the  proper 


268  GENETIC    PSYCHOLOGY 

adjustments,  as  the  situation  varies  at  each  moment.  The 
sensory  motor  intelligence  shown  by  the  goat  in  leaping  with 
absolute  accuracy  from  rock  to  rock  involves  an  accuracy 
of  adjustment  of  apparatus  quite  comparable  to  that  of 
the  instruments  used  by  the  engineer.  Such  adjustments 
as  these,  and  others  shown  by  animals  in  seeking  prey  or 
in  avoiding  enemies,  are  marvelous  examples  of  the  adap- 
tation of  means  to  ends  favorable  to  the  existence  of  the 
animal,  that  are  largely  inherited.  They  are  scarcely 
surpassed  by  anything  that  man  can  do  in  the  way  of  sen- 
sory motor  adjustments  and  only  slightly  surpassed  by  his 
more  conscious  intellectual  activities. 

Sensory  motor  activity  may  or  may  not  be  accompanied 
by  consciousness.  The  accuracy  with  which  such  activity 
is  carried  on  is  in  many  instances  decreased  rather  than  in- 
creased by  consciousness  of  what  is  being  done,  or  more 
especially,  consciousness  of  just  how  the  movements  are 
being  made.  Instinctive  and  mechanically  habitual  acts 
are  usually  more  perfectly  performed  when  there  is  little 
or  no  consciousness  of  how  they  are  being  done.  In 
the  acquisition  of  new  modes  of  reaction,  as  previously 
indicated,  consciousness  is  not  necessary,  although  it 
may  be  very  helpful.  When  it  is  helpful,  it  is  not  so 
much  by  revealing  just  what  is  being  done  and  the  exact 
character  of  the  stimuli  and  movements  involved,  as  it 
is  in  showing  the  results  of  what  has  been  done  and 
their  relation  to  the  end  to  be  gained.  The  ball  player 
who  sees  a  ball  start  in  a  certain  direction  runs  to  the 
exact  spot  where  the  ball  is  to  alight,  puts  out  his  hands 
at  just  the  right  time,  and  moves  them  in  just  the  right 
way  to  catch  the  ball  without  pain  to  himself,  is  not  con- 


TYPES  OF  ADAPTIVE  ACTIVITY  OR   INTELLIGENCE     269 

scious  of  the  exact  visual  and  kinaesthetic  sensations  he 
is  experiencing  and  the  kinds  of  movement  he  is  making. 
His  consciousness  simply  tells  him  what  he  is  trying  to 
do  and  whether  he  is  approaching  success  or  not.  When 
learning  to  catch,  he  was  conscious  of  some  of  the  sen- 
sations involved  and  the  kinds  of  movement  to  be  made, 
but  only  of  those  that  were  most  necessary  in  modifying 
his  movements  so  as  to  be  successful. 

The  same  truth  holds  regarding  our  more  conscious  ac- 
tivities of  perception  in  which  movement  is  not  so  promi- 
nent. In  perceiving  objects  we  are  not  conscious  of  the 
exact  sensations  that  they  give  us,  but  only  of  what  they 
mean  in  relation  to  purposes  that  we  are  seeking  to  realize. 
The  same  object  in  different  positions  and  at  different  dis- 
tances gives  us  different  sensations,  but  we  are  not  con- 
scious of  these  differences  only  in  so  far  as  some  practical 
need  may  have  made  discrimination  necessary.  The 
image  produced  on  the  retina  by  a  rectangular  object 
varies  greatly,  but  the  object  seems  the  same  to  us.  It  is 
also  true  that  we  may  judge  with  a  good  deal  of  accuracy 
the  distance  of  an  object  from  us  and  yet  be  entirely  uncon- 
scious of  the  sensations  that  are  the  basis  of  that  judgment. 
The  amount  of  retinal  surface  affected,  the  movements 
of  accommodation,  fixation,  and  the  fusion  of  the  two 
images,  as  well  as  variations  in  brightness  and  in  relation 
to  other  stimulating  objects,  influence  our  judgments,  as 
is  shown  by  varying  the  stimulations  and  movements; 
but  we  are  not  conscious  of  the  exact  sensations  involved 
and  of  the  precise  nature  of  the  change  that  has  been 
produced,  but  only  of  the  significance  of  the  results  of 
all  of  these. 


270  GENETIC    PSYCHOLOGY 

REPRESENTATIVE   INTELLIGENCE 

Imagination  and  memory  are  characteristic  manifesta- 
tions of  representative  intelligence.  Unlike  sensory  motor 
intelligence,  this  form  is  not  concerned  with  present 
stimulations,  but  functions  by  means  of  stored  up  impres- 
sions received  at  other  times  and  places.  In  sensory  motor 
intelligence  there  is  more  or  less  immediate  movement  so 
as  to  properly  adjust  the  body  to  external  stimulations. 
In  representative  intelligence  there  may  be  no  motion  made, 
or  if  there  is,  it  may  be  directed  in  accordance  with  past 
impressions  rather  than  according  to  the  stimulations  be- 
ing received  at  the  time. 

The  apparatus  concerned  in  representative  intelligence, 
if  not  wholly  different  from  that  concerned  in  sensory 
motor  intelligence,  at  least  functions  in  a  different  way,  so 
that  the  result  is  the  same  as  if  the  apparatus  were  wholly 
different.  The  apparatus  of  sensory  motor  intelligence  is 
modified  by  experience  so  that  the  next  time  the  same 
external  stimuli  are  received  the  reaction  is  different  be- 
cause of  the  change  in  the  mechanism.  For  example,  a 
child  sees  its  mother  sweeping  without  making  any  response 
at  the  time,  but  the  next  day  it  may  go  through  the  motions 
of  sweeping.  Thus  the  representative  apparatus  serves 
as  a  means  of  disconnecting  sensory  activity  from  motor 
activity.  When  the  sensory  apparatus  is  stimulated,  the 
motor  apparatus  is  usually  called  into  play ;  but  where  there 
is  a  representative  apparatus,  the  impulses  originated  may 
pass  almost  wholly  to  the  representative  center  and  produce 
modifications  in  that  apparatus  with  little  or  no  activity 
of  the  motor  centers.     At  some  future  time  this  activity 


TYPES  OF   ADAPTIVE  ACTIVITY  OR   INTELLIGENCE     271 

of  the  representative  center  may  be  re-excited  and  impulses 
sent  to  the  motor  center,  ])roducing  movements  which 
might  have  occurred  in  the  original  experience  had  there 
been  no  representative  center  to  divert  the  impulse  and 
disconnect  the  sensory  stimulus  and  the  motor  response. 

The  possession  of  representative  intelligence  makes  it 
possible,  not  only  for  movements  to  be  directed  by  past 
experiences  instead  of  by  present  stimulations,  but  it 
makes  economy  of  movement  possible,  images  taking  the 
place  of  actual  movement.  In  trying  to  open  a  fastening, 
an  animal  or  a  child  manipulates  it  in  various  ways,  until, 
by  chance,  the  right  movement  is  made;  while  an  adult 
may  look  at  it,  note  what  holds  it,  and  represent  the  effect 
of  moving  any  part  of  it,  and  then  make  just  the  one  move- 
ment necessary  to  undo  the  fastening.  A  small  child,  in 
putting  boxes  of  different  sizes  one  within  another,  pushes 
them  together  in  various  ways  until  they  happen  to  be 
properly  turned  and  one  goes  inside  of  the  other.  In 
piling  up  blocks  he  also  tries  various  blocks  for  a  given 
])lace.  An  older  child  will  look  at  the  boxes  and  see  how 
they  must  be  turned  in  order  that  one  may  go  inside  of  the 
other,  without  making  the  various  trial  movements ;  and  in 
using  blocks  he  looks  at  the  various  blocks  before  him  and, 
without  picking  up  each  one  and  trying  it,  selects  the  right 
one  to  fill  the  place.  If  there  is  none  before  him  that  will 
fit,  he  may  go  into  another  room  and  get  a  block  which  he 
remembers  to  have  left  there  and  put  it  in  place.  Lindley, 
in  his  experiments  with  a  puzzle,  the  lines  of  which  were 
traced  without  raising  the  pencil,  found  that  children  began 
at  once  to  draw  lines,  while  older  people  represented  the 
result  of  drawing  lines  from  various  points  and  sometimes 


272  GENETIC   PSYCHOLOGY 

drew  only  after  they  had  solved  the  puzzle  by  means  of 
mental  images  or  concepts. 

Representative  intelligence  is  not  only  a  means  of  direct- 
ing movements  without  present  stimulation  and  of  econ- 
omizing movements,  both  of  which  are  of  considerable  value 
in  the  struggle  for  existence,  but  it  also  serves  as  a  means  of 
satisfying  psychical  needs.  When  this  form  of  intelligence 
has  developed,  pleasure  and  pain  not  only  have  a  biologi- 
cal value  in  promoting  activity  that  is  favorable  to  self- 
preservation,  but  they  have  a  psychical  value,  ministering 
to  the  mental  needs  of  the  individual.  Representation 
of  past  experiences  makes  it  possible  to  experience  again 
the  pleasure  and  pain  that  formerly  accompanied  them. 
These  feelings  are  often  heightened  by  contrast  between 
the  present  and  former  situation.  In  thus  reproducing 
past  experience  a  pleasurable  outcome  may  be  emphasized 
and  the  painful  experience  leading  to  it  utilized  for  contrast, 
so  the  memories  of  painful  experiences  may  sometimes  be 
enjoyed  in  retrospect. 

It  is  also  possible  to  select  from  past  experiences  pleas- 
urable elements,  and  combine  them  in  our  daydreams 
and  in  our  ambitious  plannings  into  representations  of  a 
possible  future.  In  man  it  is  certainly  true  that  the  pleas- 
ures of  reminiscence  and  of  imagination  are,  in  the  sum 
total,  greater  than  the  pleasure  of  actual  sensory  experience. 
^Esthetic  pleasure  also  depends  largely  upon  representative 
activity. 

It  is  impossible  for  animals,  none  of  which  have  repre- 
sentative intelligence  developed  to  any  considerable  extent, 
to  experience  the  pleasures  of  reminiscence  or  dreams  of 
the  future.     Their  pleasures  must  be  derived  from  sen- 


TYPES  OF  ADAPTIVE  ACTIVITY  OR  INTELLIGENCE    273 

sory  stimulations  and  anticipatory  or  perceptual  images 
immediately  excited  by  such  stimulation.  This  is  all 
that  is  required  for  the  biological  ends  of  self-preservation 
in  animals,  but  man's  psychical  welfare  demands  more. 

The  practical  value  to  man  of  representative  intelligence 
is  shown  not  only  in  directing  and  economizing  movements 
in  the  usual  situations,  but  also  in  learning  to  meet  new 
ones.  Without  this  form  of  intelligence,  little  or  nothing 
can  be  learned  except  by  actual,  performance  by  the  in- 
dividual, resulting  more  or  less  accidentally  in  success. 
A  creature  possessing  representative  intelligence  can  learn 
by  observing  the  actions  of  others,  or,  in  other  words,  by 
imitation.  It  is  possible  thus  to  gain  images  by  which 
movements  may  be  directed  without  the  more  direct  sen- 
sory experience  of  making  the  movement.  This  is  of  great 
help,  not  only  in  eliminating  useless,  trial  movements  in 
learning  any  given  mode  of  reaction,  but  it  is  a  short  cut 
to  developing  the  representative  apparatus  so  that  it  may, 
under  various  circumstances,  effectively  direct  movements 
in  new  situations  involving  some  of  the  same  elements. 

The  possibilities  of  representative  intelligence  are  very 
much  increased  by  the  fact  that  impressions  may  be  as- 
sociated with  sensory  symbols  which  will  serve  to  arouse 
representative  activity  in  the  same  way  as  do  sensory 
experiences  of  the  objects  and  movements  themselves. 
There  is  almost  no  limit  to  the  possibility  of  arousing  the 
representative  a])paratus  to  activity  in  any  desired  way  by 
means  of  symbols,  especially  visual  and  auditory  words. 
It  is  possible  for  a  creature  possessing  representative 
intelligence  to  thus  learn  from  the  experiences  of  others 
without  himself  observing  those  experiences.     Knowledge 


274  GENETIC   PSYCHOLOGY 

of  favorable  or  unfavorable  conditions  and  modes  of  effec- 
tively securing  or  avoiding  each,  may  thus  be  gained 
without  actually  going  through  the  experience  and  even 
without  seeing  another  go  through  it.  Representative 
intelligence  therefore  has  great  biological  value  as  well  as 
psychical  value  to  a  social  creature  such  as  man.  Animals 
may  receive  warning  of  danger  by  seeing  or  hearing  com- 
panions trying  to  escape,  but  man  may  get  a  very  definite 
idea  of  a  danger  and  of  how  to  avoid  it  by  means  of  oral 
or  written  words. 

The  difference  between  man  and  even  the  highest  ani- 
mals is  very  clearly  evident  when  we  review  what  may  be 
done  by  a  creature  possessing  representative  intelligence 
and  observe  to  how  slight  an  extent  do  animals  show  evi- 
dence of  any  such  form  of  activity.  Even  the  very  simplest 
form  of  representative  intelligence,  that  of  learning  by  the 
experience  of  another,  is,  as  we  have  already  seen,  not 
shown  in  the  imitation  of  new  acts  by  animals  observed 
under  experimental  conditions.  The  common  experience  of 
persons  familiar  with  animals  will  also  verify  this  statement, 
that  one  animal  rarely  learns  by  the  experience  of  another. 
If  one  horse,  dog,  or  cat  does  something  and  is  punished 
in  the  presence  of  a  companion,  he  alone,  and  not  the  com- 
panion who  saw  the  act  performed,  learns  to  avoid  that  act. 

In  the  lower  races  of  man  and  in  the  lower  types  of 
individuals  among  civilized  men,  deficiency  in  representa- 
tive intelligence  is  shown  especially  in  the  lack  of  provision 
for  the  future,  even  though  the  necessity  of  such  provision 
would  seem  to  have  been  taught  by  previous  painful  ex- 
perience. Present  experiences  largely  dominate  the  activ- 
ity, and  reminiscences  of  the  remote  past  and  anticipations 
for  the  distant  future  have  little  influence  upon  conduct. 


TYPES  OF  ADAPTIVE  ACTIVITY  OR  INTELLIGENCE     275 

In  lower  grades  of  idiocy  there  is  such  a  comj)lete  ab- 
sence of  representative  intelligence  that  learning  is  wholly 
by  the  trial  and  success  method.  Such  an  individual  may 
try  again  and  again  to  put  a  large  object  in  a  small  hole 
or  a  hole  of  a  different  shape.  In  an  individual  of  a  little 
higher  type  the  lowest  form  of  representative  intelligence 
may  be  shown  in  a  high  degree  of  ability  to  imitate  sounds 
and  movements  of  others.  In  such  cases,  however,  the 
imitations  are  usually  made  immediately  upon  the  percep- 
tion of  the  act.  They  do  not  result  in  the  power  to  perform 
the  act  when  it  is  not  being  observed  or,  if  they  do,  it  is 
performed  literally  and  without  variation  to  meet  new 
situations,  and  without  selection  of  parts  of  the  act  and 
their  combination  into  new  and  complex  forms  of  action. 

CONCEPTUAL   INTELLIGENCE 

This  form  of  intelligence  includes  what  is  usually 
described  in  psychology  as  thinking  processes,  such  as 
abstraction,  generalization,  conception,  judgment,  and 
reasoning.  Like  representative  intelligence,  it  functions 
by  means  of  past  experiences  instead  of  present  stimula- 
tions. It  is  further  removed  from  sensory  motor  activity 
than  are  representative  processes.  It  involves  a  finer 
analysis  of  situations  and  a  separation  of  elements,  not 
only  from  many  particular  situations,  but  from  any  com- 
bination in  which  they  have  been  experienced.  It  involves 
a  re-grouping  of  elements,  not  as  they  are  found  grouped 
in  objects  and  situations,  but  according  to  similarities 
and  in  relations  by  which  purposes  may  be  served. 

The  apparatus  concerned   in  conceptual  activity  is,  in 


276  GENETIC   PSYCHOLOGY 

part  at  least,  different  from  that  concerned  in  representa- 
tive activity ;  but  it  is  primarily  excited  to  action  by  impulses 
from  the  representative  centers.  The  conceptual  appara- 
tus is  capable  of  more  fmely  differentiated  activity  and  of 
very  much  greater  capacity  for  rapid  and  various  adjust- 
ments, and  exercises  a  much  greater  influence  in  directing 
and  unifying  other  activities. 

The  final  motor  reaction  to  a  situation  may  be  objec- 
tively the  same  w^hen  determined  by  conceptual  intelligence 
as  virhen  directed  by  representative  or  perceptual  intelli- 
gence. For  example,  in  jumping  from  a  moving  car  an 
animal  or  a  person  may  respond  to  the  sensory  stimuli 
involved  in  the  situation  in  accordance  with  many  ex- 
periences of  jumping  from  cars  with  more  or  less  favorable 
results.  A  person  without  much  experience  of  this  kind 
may  direct  his  movements  in  accordance  with  a  mental 
image  of  the  movements  he  has  seen  made  by  other  persons 
under  similar  circumstances,  while  a  person  who  had 
never  had  any  experience  in  alighting  from  a  moving  ob- 
ject, and  had  never  seen  any  other  person  perform  the  act, 
might  direct  his  movements  in  accordance  with  his  general 
knowledge  of  the  laws  governing  moving  bodies  so  as  to 
jump  in  the  same  direction  that  the  car  is  moving,  just 
as  did  the  others.  The  ideas  of  force,  direction,  gravity, 
etc.,  used  by  the  one  who  directs  his  activity  by  conceptual 
intelligence  have  been  derived  from  sensory  and  represen- 
tative experiences,  but  they  are  entirely  free  from  connec- 
tion not  only  with  any  particular  kind  of  situation  but 
from  any  object  or  place. 

In  performing  an  act  like  that  described  above,  concep- 
tual intelligence  is  likely  to  be  less  successful  than  either 


TYPES  OF  ADAPTIVE  ACTIVITY  OR   INTELLIGENCE     277 

representative  or  sensory  motor,  yet  it  is  capable  of  serving 
practical  purposes  in  entirely  new  situations,  while  sensory 
motor  intelligence  is  elTective  only  where  the  individual  has 
himself  had  a  great  deal  of  experience  of  just  that  kind,  and 
while  representative  intelligence  would  be  of  little  value 
if  the  individual  had  not  himself  had  similar  experiences 
or  had  not  had  the  opportunity  to  observe  how  others 
meet  such  a  situation. 

The  less  the  accomplishment  of  an  end  involves  the 
direct  placing  of  materials  by  one's  own  movements,  the 
less  effective  his  sensory  motor  intelligence  and  the  more 
effective  the  conceptual  intelligence,  while  representative 
intelligence  is  intermediate  between  the  two.  If  a  way 
is  to  be  found  across  a  stream,  a  creature  possessing  per- 
ceptive intelligence  only  will  run  up  and  down  the  stream, 
going  out  on  points,  stones,  or  logs,  and  may  thus  acci- 
dentally find  a  means  of  getting  across.  A  person  pos- 
sessing representative  intelligence,  without  necessarily 
going  to  the  various  projecting  points,  would  look  to  see 
if  there  were  any  passage  across.  If  there  were  not,  he 
might,  without  going  to  them,  look  to  see  if  there  were 
any  boards  or  logs  that  could  be  placed  across  projecting 
points  and  stones  in  such  a  way  as  to  make  a  bridge,  or  he 
might  remember  that  there  was  such  material  to  be  ob- 
tained, and  judge  of  its  fitness  by  comparing  his  mental 
image  of  it  with  the  spaces  to  be  bridged.  An  engineer, 
on  the  other  hand,  directing  his  activities  by  conceptual 
intelligence,  might,  by  the  use  of  his  transit  and  mathemati- 
cal calculations,  determine  the  distance  to  be  bridged,  and 
kind  and  dimensions  of  materials  needed  to  construct  a 
bridge  that  would  sustain  itself  and  the  person  or  vehicles 


278  GENETIC   PSYCHOLOGY 

that  would  pass  over  it,  and  send  an  order  to  the  city  for 
the  materials  and  workmen.  He  could  do  this  without 
definitely  imaging  the  materials  needed  and  the  movements 
involved  in  placing  them.  The  symbols  used  by  him 
take  the  place  of  objects,  and  in  his  consciousness  concepts 
may  wholly  take  the  place  of  images. 

If  a  fire  breaks  out  in  a  city,  a  creature  possessing  sen- 
sory motor  intelligence  acts  only  when  his  senses  are 
directly  affected  by  the  fire  or  the  actions  of  compan- 
ions, while  one  possessing  representative  intelligence  may 
respond  to  the  cry  of  fire  without  directly  perceiving  it, 
perhaps  by  sitting  still  and  picturing  in  detail  the  flames, 
curling  smoke,  falling  buildings,  the  rushing  crowd,  etc. ; 
while  one  dominated  by  conceptual  intelligence  may  note 
the  number  of  the  fire  signal,  think  of  the  direction  of  the 
wind,  and  without  any  detailed  imaging,  know  at  once  that 
the  building  that  he  is  in  is  threatened  and  then  take  the 
proper  means  to  secure  his  safety.  He  can  thus  grasp 
the  essentials  of  the  situation  and  begin  making  the  proper 
reactions  to  a  danger  that  he  has  neither  directly  per- 
ceived nor  definitely  imaged.  He  could  perhaps  image 
the  details,  but  under  the  circumstances  it  would  be  a  waste 
of  time  and  energy  to  do  so.  In  dealing  with  abstractions 
images  may  be  a  hindrance,  e.g.  in  geometrical  reasoning 
figures  are  conceived  without  color,  weight,  taste,  etc., 
and  reasoning  is  then  made  much  simpler  and  more  ac- 
curate. Many  people  engaged  a  great  deal  in  mathemati- 
cal and  other  forms  of  abstract  reasoning  often  lose  the 
habit  and  sometimes  the  power  of  imaging.  Conceptual 
activity  therefore  plays  the  same  part  in  making  images 
unnecessary  that  representative  activity  plays  in  avoiding 
useless  movements. 


TYPES  OF  ADAPTIVE  ACTIVITY   OR   INTELLIGENCE     279 

Conceptual  intelligence  not  only  makes  it  possible  to 
accomplish  some  purposes  more  quickly  and  effectively 
than  by  sensory  motor  or  representative  intelligence,  and 
to  meet  new  situations  which  could  not  be  reacted  to  effec- 
tively by  any  other  form  of  intellectual  process,  but  it 
enables  one  to  go  beyond  what  can  be  experienced  or  even 
represented.  It  is  possible  to  perceive  or  to  represent 
two,  three,  five,  ten,  or  a  hundred  objects,  especially  if 
they  are  properly  grouped.  It  would  not  be  possible 
either  to  perceive  or  to  represent  a  million  objects  as  a 
million,  though  it  would  be  possible,  by  spending  a  number 
of  days,  to  perceive  or  represent  a  series  of  objects  amount- 
ing in  number  to  a  million.  One  can,  however,  in  a  mo- 
ment form  an  accurate  conception  of  a  million  and  almost 
as  easily  of  a  million  million.  To  conceive  of  an  object 
as  a  million  times  as  large  as  the  largest  object  that  has 
ever  been  seen  or  one  millionth  the  size  of  the  smallest 
object  that  has  ever  been  observed,  is  not  difficult,  but  to 
represent  such  objects  is  utterly  impossible.  We  cannot 
represent  space  as  having  more  than  three  dimensions, 
but  the  mathematician  readily  conceives  such  a  space 
and  has  determined  the  mathematical  laws  of  its  relations 
with  as  much  certainty  as  those  of  a  space  of  three  dimen- 
sions. The  fact  that  conceptual  intelligence  can  deal  with 
relation  regardless  of  things  gives  it  this  power. 

As  already  noted,  auditory  and  visual  symbols  are  of 
great  advantage  to  representative  intelligence,  helping  to 
free  elements  from  particular  situations,  and  making 
it  possible  for  an  individual  to  profit  by  the  experiences 
of  others  through  the  medium  of  words.  The  part  played 
by  symbols  in  conceptual  processes  is  even  more  impor- 


28o  GENETIC   PSYCHOLOGY 

tant.  Without  words,  there  could  be  very  little  conceptual 
activity,  and  some  persons  think  there  could  be  none. 
Words  may  be  introduced  into  any  situation,  and  any 
element  or  relation  of  elements  that  has  received  attention 
may  be  associated  with  a  word,  which  then  serves  to 
present  it  to  consciousness  in  the  absence  of  that  situation. 
Elements  of  various  situations  that  have  become  freed 
from  their  associates  by  means  of  words  may  be  combined 
in  any  desired  way  and  the  combination  associated  with 
and.  held  together  by  means  of  a  word.  Words  thus  serve 
to  organize  the  elements  of  experience,  and  it  becomes 
possible  for  the  concept  thus  formed  to  function  inde- 
pendently of  any  particular  situation  and  obviates  the 
necessity  of  forming  images  of  the  elements  from  which 
the  concept  was  formed.  Without  words,  by  means  of 
which  elements  may  be  more  completely  isolated  from 
their  associates  and  any  combination  of  elements  held 
together  and  organized,  the  development  of  concepts 
would  be  almost  if  not  quite  impossible. 

The  possibilities  of  the  human  brain  as  a  mechanism 
of  intelligence  are  still  further  increased  by  grouping  a 
large  number  of  ideas  that  for  certain  purposes  may  be 
considered  as  alike,  and  letting  some  symbol  stand  for 
that  group  of  ideas  which  may  then  be  treated  just  as  if 
it  were  a  single  idea.  A  single  word  thus  takes  the  place 
of  a  large  number  of  images.  The  thought  of  a  sentence 
held  in  mind  by  a  single  word  may  take  the  place  of  the 
whole  sentence.  In  a  similar  way  the  thoughts  of  a  para- 
graph, of  a  chapter,  of  a  book,  or  even  of  entire  departments 
of  science  may  be  held  in  mind  by  means  of  a  title  or  name 
and  may  be  considered  for  certain  purposes  as  a  unit  to 


TYPES  OF  ADAPTIVE  ACTIVITY  OR   INTELLIGENCE     281 

be  compared  with  other  paragraphs,  chapters,  books,  or 
departments  of  science.  By  means  of  this  power  of  se- 
lecting and  grouping,  the  mind  is  enabled  in  a  few  seconds 
to  deal  with  the  most  complex  situations  with  much 
greater  accuracy  than  would  be  possible  by  means  of 
hours  or  pcrhajjs  months  of  sensory  motor  and  representa- 
tive activity.  The  architect  and  the  engineer  may  thus, 
in  a  few  days,  plan  in  detail  structures  that  will  require 
months  of  sensory  motor  and  representative  activity  of  an 
army  of  men  to  execute. 

THE    FOUR    TYPES    OF   INTELLIGENCE    IN   MAN 

In  man  we  find  all  four  types  of  intelligence  manifested. 
He  possesses  physiological  intelligence  in  a  high  degree. 
He  can  live  in  every  variety  of  climate,  and  can  adapt 
himself  to  sudden  changes  and  endure  fatigue  as  well, 
if  not  better,  than  any  other  animal.  In  sensory  motor 
intelligence,  also,  man  is  not  inferior  to  the  most  gifted  of 
the  animals,  although  some  of  them  surpass  him  in  special 
forms  of  accurate  movement  and  in  discriminative  ability, 
yet  in  general  he  is  capable  of  acquiring  variety  and  pre- 
cision of  movement  and  discrimination  not  surpassed  by 
any. 

As  to  representative  and  conceptual  intelligence,  even 
the  highest  animals  show  little  of  the  former  and  none  of 
the  latter. 

Individual  human  beings  are  endowed  with  these  various 
forms  of  intelligence  in  greatly  dilTering  degrees.  Those 
who  are  favored  with  a  high  degree  of  physiological  in- 
telligence have  the  strength,   energy,   and   endurance  for 


282  GENETIC    PSYCHOLOGY 

accomplishing  many  and  difficult  tasks.  All  the  vital 
organs,  the  heart,  lungs,  and  digestive  system,  are  perfectly 
de\eloped,  capable  of  sustained  and  harmonious  activity, 
susceptible  to  adaptive  changes  and  capable  of  retaining 
permanently,  acquired  modifications.  The  one  thus 
endowed  by  heredity  and  by  normal  healthful  growth 
and  development  has  an  admirable  foundation  for  success 
in  physical  and  mental  activities.  Unless  thus  endowed 
one  cannot  reach  the  highest  degree  of  success,  yet  the 
mere  possession  of  such  a  physiological  endowment  does 
not  insure  efficiency  in  other  forms  of  intelligence. 

One  endowed  with  exceptionally  perfect  sensory  motor 
apparatus,  accurately  adjusted,  is  capable  of  responding 
to  immediate  sensory  stimulation  with  extraordinary 
rapidity  and  accuracy.  Such  a  one  may  execute  with  the 
greatest  ease  and  accuracy  the  most  difficult  forms  of  re- 
sponsive and  constructive  activity.  The  athlete,  the  skilled 
artisan,  artist,  and  singer  are  thus  highly  endowed  with 
sensory  motor  apparatus  that  makes  it  possible  for  them 
to  do  with  ease  what  would  be  utterly  impossible,  even 
after  long  practice,  to  others  with  less  perfect  sensory 
motor  apparatus  of  the  kind  needed ;  e.g.  the  construction 
of  the  throat  makes  the  sounding  of  high  notes  easy  to 
one  and  utterly  impossible  to  others. 

On  the  other  hand,  deficiency  in  the  sensory  motor 
apparatus  does  not  necessarily  mean  deficiency  in  the 
other  forms  of  intelligence.  Persons  of  health  and  vigor 
may  be  clumsy  and  slow  in  their  sensory  motor  reactions, 
and  those  with  deficient  sense  organs  or  with  imperfect 
muscular  development  may  possess  an  unusual  degree  of 
representative  or  conceptual  intelligence.     Even  the  entire 


TYPES  OF  ADAPTIVE  ACTIVITY   OR   INTELLIGENCE     283 

absence  of  some  of  the  special  senses  is  no  absolute  bar  to 
the  working  of  the  representative  and  thinking  intelligence. 
If  there  is  sufficient  external  stimulation  to  start  the  de- 
velopment of  the  representative  and  concei)tual  centers 
of  the  cortex,  they  may  continue  their  activity  and  develop- 
ment independently.  This  is  shown  in  a  striking  way  in 
the  education  and  development  of  Laura  Bridgman  and 
Helen  Keller,  the  latter  of  whom,  though  deprived  of  the 
two  senses  most  used  by  human  beings,  has  attained  a 
development  of  representative  and  conceptual  intelligence 
far  superior  to  that  of  the  average  human  being. 

One  who  is  highly  endowed  with  vigorous  representative 
centers  is  capable  of  imaging  with  great  vividness  and 
of  reproducing  past  experiences  after  either  long  or  short 
periods  of  time  with  great  accuracy.  There  are  individuals 
who  are  capable  of  producing  such  clear  images,  as,  for 
instance,  that  of  the  printed  page,  that  they  can  examine 
its  parts  with  almost  as  much  ease  as  is  possible  in  ordinary 
sense  perception.  There  have  also  been  persons  who 
could  read  a  book  through  once,  and  then  repeat  it  word 
for  word.  Other  individuals  possess  extraordinary  fa- 
cility in  producing  and  combining  in  all  sorts  of  ways  images 
of  various  kinds,  as  is  perhaps  best  shown  in  imaginative 
literature,  but  it  is  also  shown  in  many  practical  and  scien- 
tific inventions. 

Conceptual  intelligence,  which  depends  upon  the  pos- 
session and  effective  working  of  the  conceptual  centers, 
may  be  possessed  in  a  very  high  degree  by  persons  who 
are  not  especially  endowed  with  the  other  forms  of  intel- 
ligence, and  even  in  cases  where  they  are  deficient  in 
physiological,  sensory  motor  and  imaginative  acti\'ity.     A 


284  GENETIC    PSYCHOLOGY 

good  philosopher  may  have  little  physical  endurance, 
slight  sensory  motor  skill  and  little  or  no  power  of  imagina- 
tion, and  yet  he  may  reason  correctly  regarding  all  forms 
of  activity.  When,  however,  the  physiological  intelligence 
fails  to  keep  the  conceptual  apparatus  in  good  working 
order,  there  is  immediate  decrease  in  conceptual  intelligence. 
It  is  safe  to  say  that  the  great  men  of  the  world  have 
usually  been  highly  endowed  with  all  forms  of  intelligence. 
They  have  been  able  to  produce  and  expend  in  the  most 
economical  way  a  large  amount  of  muscular  and  nervous 
energy,  have  possessed  strength  and  skill,  and  have  been 
able  to  direct  their  imaging  and  thinking  effectively,  not 
only  because  they  possessed  all  types  of  intelligence,  but 
because  these  types  were  harmoniously  combined. 

REFERENCES 

BooDiN,    John  E.     Mind  as  Instinct,  Psych.  Rev.,  Vol.  XIII,  pp. 

121-139. 
*BoLTON,    T.    L.     A    Genetic   Study   of  Make-believe,  Jr.  Phil. 

Psych.  b'Sci.  Meth.,  Vol.  V,  pp.  281-288. 
♦BtTRROUGHS,  John.     The  Reasonable  but  Unreasoning  Animals, 

Otitlook,  Vol.  85,  pp.  809-815. 
Burke,  F.     From  Fundamentals  to  Accessory  in  the  Development  of 

the  Nervous  System  and  of  Movements,  Ped.  Sent.,  Vol.  VI, 

pp.  5-64. 
BuRNHAM,  W.  H.     The  Hygiene  and  Psychology  of  Spelling,  Ped. 

Sent.,  Vol.  XIII,  pp.  474-501. 
Brown,  H.  W.     Some   Records  of  Thoughts  and  Reasonings  of 

Children,  Ped.  Sent.,  Vol.  II,  pp.  356-396. 
*Dawson.     Levels  of  Development,  Jr.  Ped.,  Vol.  XVIII,  pp.  9-24. 
Dewey,  John.     The  Reflex  Arc  Concepts  in  Psychology,  Psych. 

Rev.,  Vol.  Ill,  pp.  357-370- 


TYPES  OF  ADAPTIVE  ACTIVITY  OR   INTELLKiENCE     285 

♦HoBHOUSE,  L.  T.      Mind  in  Evolution,  Chapters  V,  XI,  XII,  XIII. 
Mitchell.     Mathematical  Prodigies,  Am.  Jr.  Psych.,  Vol.  XVII, 

pp.  61-143. 
Morgan,  C.  L.     Comparative  Psychology,  Chapters  X,  XIII,  XIV, 

XV,  XVI. 
PiLLSBURY.     The  Psychology  of  Attention,  Chapters  VII,  X,  XIV, 

XV. 
RiBOT,  Th.     Creative  Imagination,  Open  Court,  1899,  p.  231. 
Rowland,  E.  H.     The  Psychological  Experience  connected  with  the 

Different  Parts  of  Speech,  Psych.  Rev.,  Monograph  Supp.,  No. 

32,  1907. 
Scripture.     Arithmetical  Prodigies,  Am.  Jr.  Psych.,  Vol.  IX,  pp. 

1-59- 

*Shepardson,  E.  a  Preliminary  Critique  of  the  Doctrine  of  Funda- 
mental and  Accessory  Movements,  Ped.  Sem.,  Vol.  XIV,  pp. 
101-116. 

Thorndike,  E.  L.     Educational  Psychology,  Chapter  IV. 

*Wasmann,  E.     Instinct  and  Intelligence. 

Psychology  of  Ants  and  of  Higher  Animals. 

Winch,  W.  H.  The  Function  of  Images,  Jr.  Phil.  Psych.  &=  Sci. 
Meth.,  Vol.  V,  pp.  337-352- 


CHAPTER   X 
TYPES   OF   LEARNING   ACTIVITY 

NATURE   OF  LEARNING 

In  correspondence  with  the  broader  meaning  of  intelli- 
gence adopted  in  the  preceding  chapter,  the  idea  of  what 
is  meant  by  learning  must  be  enlarged.  Each  organism 
and  each  organ  has  characteristic  modes  of  functioning, 
and  any  change  produced  by  experience  in  the  usual  mode 
of  functioning,  whether  it  be  in  an  amoeba  or  in  man,  in 
a  vital  organ  like  the  heart,  or  in  an  organ  of  consciousness 
such  as  the  cortex,  is,  in  the  broader  meaning  of  the  word, 
an  instance  of  learning.  In  this  broader  sense  the  stomach 
learns  to  digest  certain  kinds  of  food  and  the  lungs  to 
function  in  a  certain  kind  of  air,  as  truly  as  the  conceptual 
centers  learn  to  deal  with  the  truths  of  a  special  science. 

The  chief  difference  in  the  different  types  of  learning  is 
that  in  some  cases  activities  already  organized  are  modified 
by  experience,  while  in  others  the  activities  are  organized 
by  experience.  The  organization  of  the  physiological 
apparatus  and,  to  a  considerable  extent,  of  the  sensory 
motor  apparatus  is  nearly  complete  at  an  early  age  in 
animals  and  children,  largely  as  the  result  of  inherited 
growth  tendencies,  while  the  activities  of  the  representa- 
tive and  conceptual  centers  are  for  a  long  period  being 
organized  chiefly  by  experience.  For  this  reason  physio- 
logical learning  and  sensory  motor  learning  are  largely  a 

286 


TYPES   OF   LEARNING   ACTIVITY  287 

matter  of  perfecting  the  existing  organization  of  activities, 
and  then  later  of  modifying  the  activities  of  parts  and  their 
relations  to  each  other,  while  representative  and  conceptual 
learning  consist  mainly  of  acquiring  new  forms  of  organized 
activity.  In  the  lower  animals  learning  consists  chiefly 
of  modification  of  apparatus  already  organized,  but  in 
the  higher  there  is  much  more  organization  of  new 
activities. 

In  a  broad  way  all  learning  is  the  result  of  activity  in 
response  to  the  particular  environment  in  which  the  crea- 
ture lives.  It  is  brought  about  by  variations  in  the  kind, 
relative  strength,  and  order  of  stimuli  exciting  activity. 
In  the  case  of  the  various  organs  of  the  body  the  learn- 
ing is  frequently  not  in  direct  response  to  a  stimulating 
environment,  but  is  produced  indirectly  by  the  modified 
activity  of  some  other  organ  or  organs.  The  stomach 
functions  somewhat  differently  when  one  uses  his  brain 
a  great  deal  than  it  does  when  he  is  engaged  in  hard  man- 
ual labor;  the  muscles  of  one  arm  are  modified  by  the 
exercise  of  the  other,  and  the  development  of  conceptual 
and  sensory  centers  is  closely  correlated  with  the  develop- 
ment of  the  representative  centers. 

Since  the  general  character  of  all  activities  is  somewhat 
different  in  different  stages  of  development,  the  modifica- 
tion produced  by  a  certain  kind  of  stimulus  will  not  be 
the  same  at  one  stage  as  at  another.  Foods  and  modes 
of  treatment  favorable  to  the  physical  and  mental  develop- 
ment in  one  stage  of  growth  may  be  very  harmful  in  a 
different  stage,  hence  an  effective  mode  of  learning  in  one 
stage  of  development  may  be  very  ineffective  when  a  differ- 
ent stage  has  been  reached. 


288  GENETIC   PSYCHOLOGY 

For  the  purposes  of  this  chapter,  learning  is  used  broadly 
to  include  haljit  formation  as  well  as  the  more  or  less 
consciously  directed  activities  that  precede  the  formation 
of  many  habits. 

THE   PHYSIOLOGICAL  TYPE   OF   LEARNING 

Physiological  processes  are  sufificiently  organized  at 
birth  to  maintain  life.  The  lungs  begin  to  function  as 
soon  as  the  air  enters  them,  and  in  a  similar  way  appro- 
priate food  is  digested  and  assimilated.  These  processes 
are  doubtless  perfected  somewhat  by  exercise,  but  physio- 
logical learning  consists  chiefly  in  adaptation  of  these 
processes  for  the  good  of  the  organism,  according  to  the 
kind  and  amount  of  food  taken  and  the  time  of  taking  it, 
the  climatic  influences  of  heat,  light,  and  moisture,  electric 
conditions,  density  and  purity  of  air,  etc.,  and  according 
to  the  kind  and  amount  of  exercise  given  the  various  or- 
gans directly  and  in  correlated,  activity  with  other  organs. 

Very  important  physiological  changes  are  produced  by 
residing  in  different  climates  and  by  engaging  in  different 
forms  of  activity,  but  physiological  intelligence  directs  and 
unifies  these  changes  for  the  good  of  the  organism.  People 
living  in  different  parts  of  the  world  and  engaged  in  differ- 
ent occupations  are  on  the  whole  surprisingly  similar  in 
size,  strength,  and  length  of  life,  although  differences  in 
complexion  and  other  minor  characteristics  are  marked. 
This  is  one  evidence  of  the  extent  to  which  physiological 
intelligence  unifies  and  adapts  changed  activities  so  as  to 
preserve  life  and  health.  Other  evidence  is  furnished  by 
cases  in  which  the  most  harmful  drugs,  vitiated  air,  and 


TYPES   OF   LEARNING   ACTIVITY  289 

improper  exercise  are  sometimes  taken  for  a  long  period 
of  time  without  destroying  life.  So  great  are  the  gradual 
modifications  sometimes  produced  that  a  sudden  change 
to  normal  food  conditions  as  regards  air  and  exercise  may 
produce  sickness  and  death.  Because  of  this  extraordinary 
power  of  the  physiological  activities  to  become  adapted 
to  the  conditions  to  which  they  are  exposed  for  a  long 
time,  it  is  difficult  for  physiologists  to  determine  even  by 
careful  experiment  what  kinds  of  food  and  exercise  arc 
best  for  an  individual.  It  is  hard  to  tell  whether  the  seem- 
ingly favorable  or  unfavorable  results  of  a  change  in  food 
and  exercise  are  an  indication  of  their  natural  suitability 
or  unsuitability,  or  are  merely  the  result  of  a  change  in 
previous  physiological   habits. 

As  a  result  of  experience  every  organ,  muscle,  and  gland, 
even  to  the  smallest  blood  vessel,  forms  habits  of  acting 
in  a  certain  way  with  a  certain  degree  of  vigor  and  perhaps 
at  certain  times.  Any  change  in  hours  of  sleeping,  eat- 
ing, or  working  may  therefore  produce  considerable  de- 
rangement of  the  physiological  processes.  Irregular  eat- 
ing and  spasmodic  activity  arc  therefore  very  unfavorable 
to  health,  especially  in  individuals  who  have  been  very 
systematic  and  regular. 

Physiological  learning  involves  not  only  the  perfecting 
and  modification  of  the  activities  of  the  vital  organs  and 
their  relation  to  each  other,  but  a  proj)cr  relation  of  their 
activities  to  the  activities  of  other  organs,  especially  to 
those  of  the  various  nerve  centers.  It  is  a  well-established 
fact  that  whenever  any  portion  of  the  body  is  active,  whether 
it  be  a  gland,  a  muscle,  or  a  nerve  center,  there  is  increased 
circulation  of  blood  in  that  part.  Although  changes  in 
u 


290  GENETIC   PSYCHOLOGY 

circulation  take  place  with  considerable  rapidity,  there  is 
reason  to  believe  that  habits  of  sending  blood  in  increased 
quantities  to  certain  organs  may  be  established  by  using 
those  organs  at  certain  times.  The  greater  effectiveness 
with  which  the  brain  works  at  certain  times  of  the  day 
may  therefore  be  regarded  as  a  result,  in  part  at  least,  of 
circulatory  habits  that  have  been  established.  So  closely 
are  all  activities  influenced  by  physiological  habits  that 
expenditure  and  conservation  of  energy,  sobriety,  sensu- 
ality, cheerfulness,  melancholy,  physical  and  mental  slow- 
ness or  quickness,  are  in  part  the  result  of  the  acquisition 
of  certain  physiological  habits. 

Since  the  physiological  activities  are  the  earliest  to 
become  organized,  it  follows  that  physiological  habits  of  a 
desirable  kind  need  to  be  formed  during  the  first  few  years. 
Proper  food  and  exercise  and  regularity  in  taking  them  are 
therefore  the  chief  forms  of  learning  to  be  desired  in  the  early 
years.  If  a  child  of  six  has  good  physiological  habits  so 
that  every  organ  of  his  body  is  in  good  working  condition 
and  in  harmonious  relation  with  every  other  part,  it  makes 
little  difference,  so  far  as  his  future  intellectual  achieve- 
ments are  concerned,  what  the  amount  or  character  of  his 
knowledge  may  be  at  that  age. 

The  response  of  the  stomach,  so  that  the  mere  sight  or 
odor  of  food  that  has  previously  made  one  ill  causes  nausea, 
is  a  result  of  physiological  learning  in  man,  quite  compa- 
rable to  the  learning  of  the  crab  to  respond  to  the  placing 
of  a  screen  that  preceded  feeding ;  while  the  readiness  of  the 
stomach  for  food  at  accustomed  times  is  comparable  to  the 
sensitiveness  of  snails  and  sea  anemones  to  waves  at  the 
time  of  high  tide  and  to  the  coming  of  animals  for  food  at 


TYPES   OF   LEARNING   ACTIVITY  291 

certain  times.     In  all  such  cases  the  learning  is  physiologi- 
cal rather  than  conscious. 


SENSORY  MOTOR  LEARNING 

Sensory  motor  learning  is  chiefly  a  process  of  establishing 
relations  between  sense  and  motor  organs  in  the  nerve 
centers  of  the  spinal  cord,  the  basal  ganglia,  and  the  sense 
and  motor  centers  of  the  cortex.  In  so  far  as  these  con- 
nections are  formed  by  the  processes  of  growth  without 
much  stimulation,  they  are  largely  physiological.  Reflex 
and  instinctive  movements,  such  as  sucking,  moving  the 
eyes  in  a  coordinated  way,  crying,  cooing,  sitting,  creeping, 
standing,  walking,  and  climbing,  are  partly  provided  for  by 
inherited  structure  and  inner  laws  of  growth,  but  they  are 
perfected  more  quickly  by  the  ordinary  stimuli  than  they 
would  be  if  such  stimuli  were  absent.  If  healthy  activity 
of  the  nervous  and  muscular  system  is  maintained,  these 
movements  may  be  made  as  the  result  of  growth  processes 
without  any  necessity  of  actual  practice  in  making  them. 
Special  practice  hastens  the  learning  of  movements,  and  in 
the  case  of  human  beings  some  of  them,  e.g.  walking,  might, 
without  definite  practice,  often  fail  to  be  acquired. 

Sensory  motor  learning  is  shown  most  clearly  in  acquiring 
reactions  to  stimuli  not  usually  reacted  to  by  the  species 
and  sometimes  in  learning  to  make  movements  unusual 
for  the  species.  Sometimes  botli  the  stimulus  and  the 
form  of  movement  are  new,  as  when  a  dog  learns  to  walk 
on  his  front  feet  in  response  to  a  word. 

In  animals  sensory  motor  learning  consists  chiefly  in 
developing  more  highly  than  is  usual  for  the  species,  the 


292  GENETIC   PSYCHOLOGY 

characteristic  reflex  and  instinctive  movements,  and  in  learn- 
ing to  make  those  movements  in  response  to  some  new 
stimulus  and  in  a  certain  series.  Animal  trainers  always 
try  to  find  some  act  which  an  animal  instinctively  or  re- 
flexly  performs  in  response  to  a  certain  stimulus.  They 
then  give  him  some  other  stimulus  before  the  usual  one,  and 
arrange  that  the  movement  shall  be  followed  by  pleasurable 
results.  For  example,  a  horse  instinctively  raises  his  foot 
and  puts  it  down  when  his  shin  is  struck.  If  the  striking 
of  the  shin  is  uniformly  preceded  by  some  other  stimulus, 
such  as  a  gesture,  a  word,  or  a  turn  of  the  eye,  he  will  learn 
to  respond  to  that  stimulus  without  his  leg  being  touched. 
Similar  associations  with  other  instinctive  movements  may 
be  made,  and  then  all  brought  together  in  such  a  way  as  to 
constitute  what  seems  to  the  observer  a  wonderful  exhibition 
of  intelligence.  Educated  horses  are  thus  made  to  appear 
to  perform  complicated  mathematical  calculations.  Their 
performances  are  truly  wonderful  as  regards  refinement  of 
discrimination  of  the  essential  stimulus.  In  some  instances 
a  horse  responds  to  changes  in  the  one  directing  his  per- 
formance that  are  unnoticed  by  human  observers  and  of 
which  the  director  himself  is  unconscious.  That  they  must 
be  made,  however,  is  proved  by  the  fact  that  if  the  face  of 
the  one  directing  the  performance  is  covered,  the  horse  is 
unable  to  perform  his  tricks.  In  the  extent  to  which 
native  sensory  motor  reactions  may  be  developed,  the 
higher  animals  are  nearly  if  not  quite  equal  to  man. 

The  child  has  many  more  sensory  motor  reactions  to 
perfect  than  most  of  the  animals,  since  his  reflex  and  in- 
stinctive movements  are  usually  less  perfect  at  birth  than 
theirs.     The  child  also,  because  of  the  peculiarity  of  his 


TYPES   OF   LKARNIXr.    ACTI\-ITY  293 

motor  apparatus,  is  capable  of  making  a  very  much  greater 
variety  of  movements  than  is  possible  to  any  animal. 
Since  every  movement  is  stimulated  and  guided  by  sensory 
impulses,  he  has  the  possibility  of  acquiring  an  almost 
infmite  number  of  connections  between  sense  stimulations 
and  movements.  If  all  of  these  associations  had  to  be  ac- 
(juired  by  the  incidental  occurrence  of  the  various  stimuli 
in  a  certain  order  so  as  to  form  a  series  or  a  complex  form 
of  activity,  he  could  acquire  in  the  course  of  a  lifetime  only 
a  small  part  of  the  associations  that  are  acquired  by  the 
child  of  three  years.  If  he  were  taught  the  combinations 
wholly  by  the  same  methods  used  in  training  animals,  he 
would  still  be  unable  to  acquire  more  than  a  small  part  of 
the  sensory  motor  connections  that  are  usually  acquired  by 
educated  children.  Fortunately  another  means  of  sensory 
motor  learning  is  opened  to  the  child.  We  do  not  in  every 
case  have  to  start  with  some  simple  reaction  and  build  on  to 
that,  as  in  case  of  animals,  but,  thanks  to  his  imitative  ten- 
dency, the  child  may  acquire  new  combinations  of  sense  im- 
pressions and  movements  in  certain  relations  to  each  other 
without  having  to  hit  upon  the  right  combination  by  chance 
movements  of  his  own.  As  has  already  been  jjointcd  out,^ 
the  realization  of  the  instinctive  tendencies  of  the  child 
depends  upon  certain  anatomical  and  physiological  con- 
nections between  the  various  sense  and  motor  centers  of  the 
cortex.  When  a  child  hears  a  sound,  the  path  from  the 
auditory  center  for  that  sound  is  more  open  toward  the  motor 
center  concerned  in  producing  the  same  sound  than  in  any 
other  direction.  A  similar  truth  holds  regarding  centers 
concerned  in  the  visual  perception  of  movement  and  the 
motor  centers  concerned  in  executing  the'^ame  movement. 


294  GENETIC    PSYCHOLOGY 

There  is  therefore  an  inherited  basis  for  the  organizations 
that  seem  to  be  produced  by  experience.  By  the  help  of  the 
imitative  tendency  the  child  is  soon  able  to  acquire  all  the 
complicated  movements  involved  in  learning  to  dress  him- 
self, in  manipulating  objects  in  countless  ways,  and  in 
handling  a  variety  of  tools  for  various  purposes. 

Learning  to  speak,  so  far  as  the  making  of  the  movements 
is  concerned,  is  also  largely  a  sensory  motor  process.  A 
child  of  two  who  has  learned  to  utter  five  hundred  words  has 
in  that  process  alone  probably  acquired  a  greater  number 
of  sensory  motor  connections  than  is  usually  acquired  by 
any  of  the  higher  animals  in  all  forms  of  their  activity 
during  a  lifetime.  Only  a  very  few  of  the  animals  have  a 
sensory  motor  apparatus  that  is  capable  of  producing  the 
sounds  involved  in  the  pronunciation  of  words.  It  is 
largely  because  of  the  great  variety  of  movement  possible  to 
the  child  owing  to  the  structure  of  his  vocal  apparatus,  and 
of  his  arm  and  hand ,  and  because  of  the  nervous  organizat  ion 
that  permits  him  to  learn,  by  means  of  imitation,  that  the 
sensory  motor  acquisitions  of  the  child  are  so  infinitely 
superior  in  number  and  variety  to  those  of  any  of  the  animals, 
though  in  inherited  organization  of  sensory  motor  appara- 
tus they  often  far  surpass  him. 

The  chief  mode  of  establishing  sensory  motor  connec- 
tions is  by  means  of  repetition  with  favorable  results.  The 
more  uniform  the  repetition,  the  more  surely  and  quickly 
will  an  association  and  a  series  of  reactions  be  established 
as  a  habit.  In  so  far,  therefore,  as  any  activity  is  to  be 
performed  in  a  sensory  motor  way  it  is  desirable  that  in 
learning  it  the  method  of  unvarying  repetition  should  be 
followed.     This   is  one  of  the  chief  maxims   of  animal 


TYPES    OF   LEARNING   ACTIVITY  295 

trainers.  Its  importance  is  well  illustrated  by  the  incident 
given  by  Bostock  of  a  trainer  who  lost  control  of  his  animals 
and  nearly  lost  his  life  because  at  a  critical  stage  in  the 
performance  of  a  trick  by  his  animals,  he  turned  to  the 
left  instead  of  to  the  right,  as  he  had  previously  done  when 
that  trick  was  being  performed. 

The  importance  of  proper  development  and  organization 
of  sensory  motor  activity  cannot  be  overestimated.  This 
may  well  be  illustrated  by  the  connections  between  visual 
impressions  that  are  perfected  by  experience  and  used 
during  every  waking  moment.  A  moving  object  stimulates 
the  periphery  of  the  eye,  and  at  once  the  head  and  eyes  are 
turned  so  that  the  points  of  clearest  vision  are  stimulated. 
In  learning  to  read  the  movement  of  the  eyes  along  the  line 
and  back  to  the  beginning  of  the  next  line  is  a  sensory 
motor  process  of  considerable  difficulty  that  must  be  ac- 
quired and  perfected.  A  little  reflection  will  show  one  how 
delicately  accurate  the  movements  of  the  eyes  must  be  to 
follow  the  lines  of  ordinary  print  successfully.  He  will 
then  perhaps  agree  that  the  more  rapid  learning  to  read  by 
children  of  the  present  day  is  due  as  much  to  wider  spaced 
printing  in  the  readers  as  to  better  methods  of  teaching.  In 
touching  objects  and  moving  them  in  any  desired  way  and 
in  making  the  proper  movements  to  intercept  a  moving 
object,  the  most  accurate  adjustment  of  sensation  and  move- 
ment is  required.  Not  until  such  sensory  motor  reflexes 
are  well  established  can  there  be  any  considerable  develop- 
ment of  manual  ability  in  the  daily  movements  of  walking, 
dressing,  etc.,  and  in  any  form  of  skill  involved  in  work  or  in 
plays  and  sj)orts.  If  one  attemj:)ts  to  guide  his  hand  in 
tracing  lines  which  are  seen   in   a  mirror  onlv,   he  will 


296  GENETIC   PSYCHOLOGY 

realize  how  important  it  is  that  the  relatively  simple 
sensory  motor  reactions  shall  be  well  developed. 

The  more  complex  perceptual  activity  that  must  be 
acquired  is  suggested  by  the  following :  children  often 
confuse  such  words  as  "saw"  and  "was,"  "on"  and 
"no,"  probably  because  in  all  their  previous  experience 
in  gaining  free  ideas,  objects,  e.g.  chairs,  are  of  the 
same  class  when  their  parts  are  the  same  no  matter 
how  they  are  turned  or  from  which  side  they  are  viewed, 
although  their  appearance  varies  greatly.  This  tendency 
is  doubtless  carried  over  into  the  perception  of  symbols, 
and  errors  are  made  because  of  ignoring  differences  con- 
sisting only  of  variations  in  arrangement  of  letters  or  digits. 
The  writer  distinctly  remembers  when  about  nine  years  old 
noticing  for  the  first  time  that  a  number  on  a  calendar  was 
not  the  same  when  read  backward. 

The  simple  sensory  motor  reactions  are  not  only  neces- 
sary to  success  in  movements  of  all  kinds,  but  also  to  accu- 
rate perception.  This  is  most  easily  demonstrated  in 
illusions.  For  example,  a  large  object  is  lifted  with  more 
vigor  than  a  small  one  of  the  same  weight,  resembling  it 
except  in  size,  and  this  is  one  reason  why  the  weight  of  the 
smaller  object  is  usually  perceived  as  much  greater  than  that 
of  the  similar  large  object.  Many  other  illusions,  especially 
of  size  and  shape,  are  caused  by  the  character  of  the  sensory 
motor    reaction  involved  in  the  perception,   e.g.    line    a 

< >  seems  shorter  than  line  b  > <  because  the  eye 

tends  to  stop  sooner  when  following  line  a.  It  is  probable 
that  the  development  of  perceptive  power  is  in  general  very 
largely  dependent  upon  the  perfecting  of  sensory  motor 
reactions.     The  play  of  the  child  by  means  of  which  the 


TYPES   OF   LEARNING   ACTIVITY  297 

simple  sensory  motor  reactions  arc  perfected  and  organized 
in  various  ways  is  therefore  one  of  the  most  important  parts 
of  his  education.  As  we  shall  see  later,  this  form  of  learn- 
ing in  its  more  complex  aspects  plays  an  important  part  in 
the  higher  intellectual  acquisitions  of  man,  especially  in 
dealing  with  the  symbols  of  images  and  concepts. 

We  have  already  given  evidence  that  the  learning  of 
animals  is  largely  sensory  motor,  since  their  learning  is 
confined  almost  wholly  to  what  is  associated  with  their 
own  movements.  We  therefore  have  an  extensive  iield  of 
learning  that  is  common  to  men  and  animals,  while  into 
another  extensive  field  man  only  can  enter. 

REPRESENTATIVE    LEARNING 

In  physiological  terms  representative  learning  involves 
the  acquisition  of  tendencies  on  the  part  of  the  representa- 
tive centers  in  the  cortex  to  function  in  certain  organized 
ways  independently  of  sensory  stimulation.  In  psychical 
terms  it  involves  the  formation  of  free  images  of  objects, 
movements,  and  symbols  independently  of  their  associates. 

Independent  action  of  representative  centers  and  the 
formation  of  free  images  is  brought  about  by  a  method 
exactly  the  reverse  of  that  most  successful  in  sensory 
motor  learning.  Instead  of  having  the  sensory  motor  ex- 
perience repeated  in  exactly  the  same  way  with  the  same 
accompaniments,  the  representative  centers  need  to  be 
excited  by  sensory  stimulations  varying  in  kind,  order,  and 
relation.  A  square  or  a  triangle  in  unvarying  surroundings 
may  serve  as  a  sensory  guide  to  a  pigeon  or  other  animal 
seeking  to  find  its  way  through  a  maze  or  to  food,  without 


298  GENETIC   PSYCHOLOGY 

the  animal  having  any  distinct  idea  of  the  figure  itself 
separate  from  its  surroundings  and  the  end  to  be  attained. 

Usually  animals  have  few  experiences  with  squares  in 
different  surroundings  or  as  means  to  different  ends.  They 
are  not  able,  therefore,  to  form  a  separate  image  of  the 
figure.  The  child,  on  the  other  hand,  has  many  objects  of 
interest  to  him  that  are  square,  and  he  has  much  experience 
in  manipulating  such  objects  and  using  them  for  various 
purposes.  His  attention  is  thus  attracted  to  the  character- 
istics of  the  figure  in  the  midst  of  various  surroundings  and 
in  the  attainment  of  a  variety  of  ends.  He  therefore  soon 
comes  to  have  a  free  image  of  the  square.  In  most  adults, 
images  of  geometrical  figures  are  for  this  reason  freer  than 
images  of  other  objects.  This  is  shown  by  the  fact  that  in 
listening  to  a  description,  the  statement  that  a  rectangle  is 
red  and  is  resting  on  its  shorter  side,  causes  no  such  shock 
of  surprise  or  reconstruction  of  the  mental  picture  as  would 
the  statement  that  a  house  previously  named  was  blue 
and  standing  with  its  chimney  downward.  For  a  similar 
reason  a  mountain  from  a  new  point  of  view  is  like  a  new 
mountain. 

Representative  learning  is  greatly  aided  by  imitation. 
The  same  act  is  observed  and  repeated  under  various 
surroundings.  This  is  especially  true  when  the  child 
imitates  what  he  has  seen  at  some  other  time  or  place. 
Such  imitation  is  often  of  the  dramatic  form  where  objects 
present  are  used  to  represent  other  objects  not  present  and 
where  the  movements  are  partially  carried  out  in  imagina- 
tion instead  of  being  actually  executed.  The  variety  in  the 
combinations  of  objects  and  acts  that  are  experienced  in 
imitative  activities  greatly  hastens  the  formation  of  free 


TYPES    OF   LEARNING    ACTIVITY  299 

images  of  them.  After  images  are  partially  developed, 
internal  repetition  of  experiences  without  motor  imitation 
hastens  and  perfects  the  process. 

Words  are  also  a  very  great  help  in  representative  learn- 
ing. The  same  sound  being  used  to  designate  an  object 
under  various  circumstances  makes  it  possible  for  the 
object  to  be  represented  when  the  word  is  heard  and  the 
object  not  present.  In  this  case  the  representative  center  is 
excited  to  activity,  not  by  the  sensory  stimulus  of  the  object 
itself,  but  by  another  form  of  sensory  stimulus  associated 
with  the  object  and  given  in  entirely  different  surroundings. 
Words  are  among  the  most  effective  means  of  producing 
action  of  the  representative  centers  without  direct  sensory 
stimulation,  because  the  excitations  of  the  center  arc  likely 
to  be  in  new  surroundings  and  in  the  absence  of  the  original 
object. 

The  first  steps  in  forming  free  images  are  taken  by 
children  in  their  manipulation  of  objects.  Manipulation  of 
objects  makes  possible  immediate  imitation  of  acts  as  seen, 
and  this  prepares  the  way  for  delayed  imitation  of  them 
under  other  surroundings.  Following  this  may  come 
association  with  word  symbols  and  imaginative  changes 
in  surroundings,  characteristics,  and  relations.  In  the 
child's  manipulation  of  objects  in  a  variety  of  ways,  in  his 
imitation  of  all  kinds  of  acts,  and  in  his  dramatic  play  and 
imaging,  he  is  organizing  his  representative  apparatus  in 
such  a  way  that  the  elements  of  all  his  past  experiences 
may  be  called  into  play  and  used  in  indirectly  acquiring 
and  interpreting  the  experience  of  others  as  expressed  in 
words,  oral  and  written.  The  apparently  useless  and  some- 
times amusing,  absurd,  or  troublesome  behavior  of  children 


300  GENETIC    PSYCHOLOGY 

is  in  reality  often  a  most  important  form  of  the  learning 
process. 

After  a  number  of  free  images  have  been  formed  and  as- 
sociated with  the  appropriate  words,  a  means  of  learning  is 
open  to  the  child  that  is  not  possible  to  any  animal.  Words 
spoken  in  a  certain  order  produce  a  corresponding  grouping 
of  free  images,  and  in  this  way  new  internal  experiences 
entirely  independent  of  present  surroundings  may  be  gained. 
In  so  far  as  the  child  has  free  images  of  the  elements  of  all 
human  experiences  and  of  the  fundamental  elements  of  the 
external  world,  he  can,  through  the  medium  of  words,  in- 
ternally experience  what  has  been  experienced  by  any 
person  in  any  portion  of  the  world  in  any  period  of  its 
history.  His  learning  is  no  longer  limited  by  time  and 
place,  but  he  is  introduced  into  an  environment  un- 
bounded in  the  possibilities  it  gives  for  representative 
learning.  These  facts  are  especially  well  illustrated  in  the 
study  of  geography  and  history. 

Animals,  on  the  other  hand,  have  no  such  means  of  learn- 
ing. It  is  true  that  they  can  learn  to  respond,  in  a  sensory 
motor  way,  to  words  that  may  be  associated  with  a  definite 
movement  to  be  made.  Words  are  most  effective  to  them 
when  spoken  in  the  same  tone  and  under  the  same  circum- 
stances, yet  some  of  the  more  intelligent  animals  may  learn 
to  respond  to  the  word  itself  under  various  circumstances. 
In  no  case,  however,  is  there  a  record  of  an  animal  being 
given  new  knowledge  by  means  of  words.  He  is  taught 
words,  but  words  cannot  be  used  to  teach  him  anything  new, 
because  he  has  no  independent  action  of  representative 
centers  by  which  the  objects  and  experiences  signified  by 
the  words  may  be  separately  represented  and  formed  into 
new  combinations  of  internal  experiences. 


TYPES   OF   LEARNING   ACTIVITY  301 

A  child  may  learn  words  even  in  a  sensory  motor  way  more 
readily  than  animals,  because  he  has  a  vocal  apparatus 
that  enables  him  to  respond  to  all  words  by  their  utterance, 
whether  he  can  give  any  other  form  of  motor  response  or 
not.  Very  young  children  easily  learn  meaningless  jingles 
and  rhymes.  Children  a  little  older  readily  learn  long 
selections  that  they  hear  repeated  frequently,  without 
necessarily  knowing  their  meaning.  It  is  also  true  that 
children  when  being  taught  to  read  may  seem  to  know  a 
word,  but  fail  to  recognize  it  when  it  appears  in  a  different 
place  or  surrounded  by  different  words.  A  long  word  may 
be  correctly  distinguished  from  the  short  words  with  which 
it  is  learned  and  then  be  named  correctly.  In  order  that 
free  images  of  visual  words  may  be  formed,  it  is  necessary 
that  they  should  be  observed  with  a  variety  of  associates. 
The  same  principle  holds  in  acquiring  free  images  of 
either  visual  or  auditory  symbols  and  in  acquiring  the 
symbolic  statements  of  the  facts  of  number,  A  child  that 
does  not  know  the  significance  of  three  may  learn  in  a 
sensory  motor  way  a  large  section  of  the  multiplication 
table. 

In  general,  practice  in  immediate  response  to  a  series 
of  sensory  stimulations  by  a  series  of  movements  with  little 
or  no  variation  in  the  repetition  results  in  sensory  motor 
learning  only,  while  the  repetition  of  a  stimulation  under 
varying  circumstances  with  different  interests  and  move- 
ments results  in  representative  learning  or  the  formation  of 
free  images.  After  many  free  images  have  been  formed, 
representative  learning  proceeds  most  rapidly  and  effec- 
tively when  the  images  are  revived  and  combined  by 
means  of  words  instead   of  having  the  original  sensory 


302  GENETIC    PSYCHOLOGY 

experience  repeated.  In  learning  the  essential  charac- 
teristics of  an  object  or  class  of  objects,  more  rapid 
progress  is  made  by  naming  the  characteristics  and  re- 
peating them  when  the  object  is  absent  than  by  repeated 
observations  without  any  naming  of  characteristics. 

CONCEPTUAL    LEARNING 

Learning  to  think  is  a  process  of  organizing  conceptual 
centers  and  getting  them  to  function  independently  of  sense 
and  representative  centers  that  are  excited  by  objects,  and 
in  association  with  those  centers  that  are  concerned  in  the 
production  of  percepts  and  images  of  words  and  other 
symbols.  The  organizing  process  is  similar  to  that  in 
representative  learning,  images  serving  as  stimuli  to  the 
conceptual  centers  in  much  the  same  way  as  sensations 
stimulate  the  representative  centers. 

The  process  of  organizing  the  conceptual  apparatus  is 
also  similar  to  that  involved  in  organizing  the  perceptual. 
The  conceptual  apparatus  is  not,  however,  organized  pre- 
vious to  experience  as  is  in  part  the  perceptual  in  some  lines, 
and  much  more  freedom  of  adjustment  is  needed  in  con- 
ceptual activity.  Free  images  instead  of  sensations  serve 
as  stimuli  for  the  organization  of  conceptual  centers,  while 
ends  to  be  gained  determine  the  adjustments,  and  words 
help  to  emphasize  these  adjustments  and  provide  for  their 
more  accurate  repetition.  In  perceptual  organization  an 
object  arousing  directly  one  kind  of  sensation  comes  to 
stimulate  indirectly  other  sense  centers  which  it  has  at  an- 
other time  stimulated  directly,  while  in  conceptual  activi""" 
a  word  or  an  image  of  a  characteristic  found  in  many  sitUt.- 


TYPES   OF   LEARNING   ACTIVITY  303 

tions  produces  an  adjustment  of  representative  apparatus 
corresponding  to  the  word,  and  there  may  be  much  or  little 
separate  activity  of  the  representative  centers  thus  ad- 
justed, according  as  the  mental  process  is  chiefly  imagina- 
tive or  conceptual;  e.g.  a  person  of  the  imaginative  type 
may  image  size,  color,  shaj)c,  and  position  of  houses,  trees, 
etc.,  when  the  words  are  heard, while  another  may  think  only 
of  their  meaning  without  definite  imagery  of  objects  or 
sensory  characteristics. 

The  method  by  which  conceptual  centers  (or  more 
properly  conceptual  adjustments)  are  most  quickly  devel- 
oped, is  much  the  same  as  that  by  wdiich  representative 
centers  learn  to  function  independently.  The  images  serv- 
ing as  stimuli  to  the  conceptual  centers  must  be  varied 
as  much  as  possible.  In  connection  with  this  variation 
there  must  be  the  distinctive  selective  process  of  attention 
and  facility  in  making  and  maintaining  adjustments,  so 
that  cognition  of  relations  is  possible. 

In  the  selection  of  common  characteristics,  purpose  is 
an  important  factor  in  determining  what  are  the  essential 
characteristics  of  various  objects  used  in  reaching  the 
desired  ends,  or,  in  other  words,  in  making  and  maintaining 
a  general  type  of  adjustment.  A  child  that  has  fre- 
quently seen  cubes  in  various  situations  may  form  free 
images  of  them,  but  in  order  that  concepts  may  be  derived 
from  his  experience  with  blocks  and  other  objects,  certain 
characteristics  must  be  made  objects  of  special  attention. 
If  the  child  has  been  using  these  objects  for  constructive 
purposes  in  connection  with  those  of  another  form,  his 
attention  is  likely  to  be  directed  toward  their  shape,  and 
h    begins  to  have  a  concept  of  form  as  a  characteristic  of 


304  GENETIC   PSYCHOLOGY 

objects.  If  the  blocks  have  varied  greatly  in  size,  and  those 
of  one  size  have  proved  better  fitted  for  certain  purposes 
than  those  of  another  size,  attention  selects  the  character- 
istic of  size,  and  the  concept  of  size  begins  to  develop.  If 
the  child  is  making  a  design  of  several  colors  in  which  he 
has  to  choose  the  block  to  use  on  the  basis  of  color,  his 
attention  will  be  directed  to  the  characteristics  of  red, 
green,  etc.  If  he  should  have  occasion  to  handle  blocks 
of  different  weight,  his  attention  would  be  called  to  that 
characteristic. 

In  deriving  such  concepts  as  those  of  form,  size,  color, 
and  weight  simpler  ideas  are  first  formed.  The  child 
develops  the  idea  of  a  square,  triangle,  rectangle,  etc.,  and 
the  meaning  of  such  adjectives  as  square,  before  he  gains 
the  more  completely  abstract  concept  of  form.  Ideas  of 
objects  as  large  or  small  for  various  purposes,  and  for  vari- 
ous classes  of  objects,  are  formed  before  there  is  the  com- 
pletely abstract  idea  of  size.  Children  sometimes  have 
difficulty  in  understanding  why  a  large  object  of  one  class, 
as,  for  example,  a  dog,  should  be  called  large  when  a  much 
larger  object  of  another  class,  as  a  horse,  is  called  small. 
A  child  also  forms  ideas  of  red,  green,  blue,  etc.,  before 
he  forms  the  more  abstract  concept  of  color.  Concepts 
of  heavy  and  light  also  precede  the  more  abstract  one  of 
weight. 

In  the  formation  of  all  such  concepts,  after  a  number  of 
free  images  have  been  gained,  it  is  no  longer  necessary  to 
actually  or  completely  represent  all  of  these  images.  A 
concept  often  involves  a  tendency  to  form,  and  a  conscious- 
ness of  the  possihility  of  forming  specific  images  of  objects 
of  various  forms,  sizes,  colors,  weights,  etc.,  but  it  may 


TYPES   OF   LEARNING   ACTIVITY  305 

function  with  little  or  no  actual  imaging.  In  this  way  the 
possibility  of  forming  distinct  images,  which  is  an  essential 
element  in  the  concept,  takes  the  place  of  their  actual 
formation,  just  as  images  take  the  place  of  actual  move- 
ments. 

The  formation  of  one  concept  prepares  the  way  for  the  for- 
mation of  another,  and  even  the  concei)t  which  has  scarcely 
begun  to  form  may  help  in  the  development  of  another  that 
has  given  it  birth ;  for  example,  a  child  who  distinguishes 
between  triangles  and  squares  does  so  in  part  because  of 
the  difference  in  the  number  of  sides,  and  when  the  idea  of 
form  is  fully  developed,  the  idea  of  number  will  be  an  essen- 
tial part  of  the  idea.  It  is  unquestionably  true,  however, 
that  children  learn  to  distinguish  triangles  from  squares 
long  before  they  can  count  and  before  there  is  any  other 
evidence  that  they  are  conscious  of  number  differences 
as  such.  The  concept  of  number  will  not  be  formed  until 
the  number  characteristic  is  singled  out  because  of  some 
practical  need  or  interest  leading  to  conscious  attention 
to  number  relations.  The  formation  of  every  concept 
gives  experiences  that  are  helpful  in  the  formation  of  other 
concepts  as  well  as  necessary  to  the  perfect  development 
of  the  concept  in  question,  but  the  experiences  that  may 
serve  as  the  basis  of  concepts  do  not  actually  become  such 
basis  until  they  have  been  selected  by  conscious  attention 
from  the  complex  in  which  they  appear. 

This  is  one  reason  why  the  logical  method  of  teaching  a 
subject  is  not  the  psychological  method  and  does  not  work 
well  especially  with  young  children.  To  a  logical  adult 
mind  it  seems  just  as  impossible  that  any  sort  of  a  concej^t 
of  a  triangle  can  be  developed  witliout  the  concept  of  num- 


3o6  GENETIC   PSYCHOLOGY 

bcr  being  first  formed,  as  it  formerly  seemed  to  teachers 
that  it  would  be  utterly  impossible  to  learn  words  without 
first  learning  the  letters  of  which  words  are  composed. 
It  may  be  stated  as  a  general  rule  that  early  concepts  are 
not  formed  by  combining  concepts  already  existing,  but 
that  they  emerge  under  the  stimulus  of  interest,  purpose, 
and  contrast  from  a  complex  that  is  as  yet  unknown  spe- 
cifically. This  is  the  reason  why  teachers  are  beginning  to 
realize  that  the  more  logical  the  method  of  presenting  a 
subject  to  an  adult  mind,  the  less  it  is  suited  to  a  young 
child. 

The  help  that  concepts  already  formed  render  to  others 
is  well  illustrated  in  the  process  of  acquiring  concepts  of 
the  meaning  of  words  not  associated  with  concrete  expe- 
riences. If  one  knows  the  meaning  of  a  few  words  of  a 
sentence  that  he  hears  or  sees,  he  can  often  form  a  pretty 
good  idea  of  the  thought  of  the  whole  sentence,  and  after 
hearing  the  unfamiliar  words  used  in  a  variety  of  sentences, 
he  comes  to  have  a  fairly  clear  concept  of  their  meaning. 
If  a  wrong  meaning  is  attached  to  the  essential  word  in  a 
sentence,  incorrect  concepts  of  words  associated  with  it 
may  of  course  be  formed.  When  new  words  are  definitely 
explained  by  means  of  known  words,  we  have  examples  of 
the  slightly  different  process  of  forming  concepts  by  com- 
bining concepts  already  existing. 

In  reading  understanding^  there  is  a  unifying  process 
in  which  the  concepts  suggested  by  every  word  are  related 
to  and  modified  by  other  words,  especially  those  immedi- 
ately preceding  and  following.  A  series  of  words  produces 
some  anticipation  of  the  words  that  are  to  come,  and  the 
words  that  are  to  follow  modify  to  som.e  extent  the  signifi- 


TYPES   OF   LEARNING    ACTIVITY  307 

cance  of  those  just  preceding.  In  ordinary  reading  the 
eyes  are  several  words  ahead  of  the  vocal  organs,  and  read- 
ing with  proper  expression  of  thought  is  impossible  without 
this  modifying  and  unifying  relation  of  all  the  words  in 
the  sentence. 

The  limitations  and  advantages  of  conceptual  intelli- 
gence are  well  illustrated  by  the  experiments  of  Professor 
Judd  upon  fifth  and  sixth  grade  boys  in  two  groups  who 
were  learning  to  strike  a  target  under  water.  To  one  group 
an  explanation  was  given  of  refraction,  which  makes  an 
object  seen  under  water  seem  to  be  disi)laced.  In  the  first 
experiment,  when  the  object  to  be  touched  was  twelve 
inches  under  water,  both  groups  were  on  an  equality, 
seeming  to  learn  in  a  sensory  motor  way  by  trial  and  error, 
but  when  the  depth  changed  to  four  inches  and  all  were 
informed  of  the  fact,  the  boys  who  understood  the  prin- 
ciple learned  much  more  rapidly,  while  the  rate  of  the 
others  remained  about  the  same.  Some  sensory  motor  ex- 
perience is  evidently  necessary,  but  having  that,  one  with 
conceptual  intelligence  and  knowledge  can  apply  his  ex- 
perience to  new  relations,  while  one  without  such  knowl- 
edge must  continue  to  learn  by  trial. 

REVERSAL    OF    RELATION    BETWEEN    LOWER    AND    HIGHER 

CENTERS 

As  we  have  already  seen,  the  representative  centers  are 
primarily  excited  by  the  sensory  motor  centers  and  the 
conceptual  centers  by  the  representative  centers,  and 
variety  in  such  excitation  helps  to  get  the  higher  centers 
ready    for    independent    activity.     They    soon    become 


3o8  GENETIC    PSYCHOLOGY 

capable  of  being  excited  by  impulses  passing  from  one 
representative  center  to  another  or  from  one  conceptual 
center  to  another,  and  by  impulses  passing  from  the  centers 
for  perceiving  and  representing  symbols.  After  they  have 
thus  become  independent  of  immediate  stimulation  from 
the  lower  centers,  there  is  need  for  a  reversal  of  the  process, 
so  that  the  higher  centers  may  send  back  stimuli  to  the 
lower,  and  thus  excite  them  to  activity.  It  is  because  of 
this  that  voluntary  control  of  movements  and  of  images 
becomes  possible. 

Usually  this  reversal  of  the  course  of  impulses  so  that 
the  higher  centers  stimulate  the  lower  to  activity  takes  place 
gradually,  and  the  fact  that  the  processes  are  distinct  has 
received  little  attention.  A  striking  example  of  the  two 
processes  carried  on  separately  is  that  of  a  little  girl  who 
began  before  the  close  of  her  first  year  to  imitate  words 
and  was  able  to  imitate  with  almost  perfect  accuracy 
every  word  that  she  heard.  At  this  time  she  made  no 
attempt  to  use  words  as  a  means  of  expressing  her  ideas. 
Later  she  began  to  do  so,  but  then  had  as  much  difficulty 
as  the  ordinary  child  in  pronouncing  words  correctly. 
Evidently  her  earlier  imitation  of  words  was  entirely  of 
a  sensory  motor  character,  while  in  her  attempts  at  speak- 
ing the  centers  for  controlling  the  vocal  organs  were  being 
excited  from  the  conceptual  and  representative  centers. 

It  is  a  well-known  fact  that  associations  may  be  very 
strong  in  one  direction  and  have  little  or  no  suggestive 
force  in  another  direction.  One  who  can  readily  repeat 
the  alphabet  or  a  quotation  may  find  it  difficult  or  impos- 
sible to  repeat  the  same  backward.  This  is  true  in  a  very 
marked  degree  of  reversing  sensory  motor  series,  such  as 


TYPES    OF  LEARNING   ACTIVITY  309 

writing  a  word  backward,  while  in  representative  and 
conceptual  activity,  where  variety  of  combinations  is  com- 
mon, the  reversal  of  the  order  of  a  series,  as  recalling  the 
events  of  yesterday,  beginning  at  the  end  of  the  day,  is  not 
difficult.  It  is  only  when  a  scries  of  ideas  has  frequently 
occurred  in  a  certain  order  that  reversal  is  difficult. 

In  the  case  of  series  involving  lower  and  higher  centers, 
reversal  is  likely  to  be  more  difficult  without  practice  than 
when  the  centers  of  higher  levels  only  are  involved.  It 
may  safely  be  stated  as  a  general  rule  that  ability  to  per- 
form an  act  in  response  to  a  sensory  stimulus  does  not 
necessarily  mean  ability  to  perform  it  in  a  voluntary,  rep- 
resentative, and  conceptual  way  and  vice  versa.  One 
who  can  perform  accurately  a  gymnastic  or  manual  exer- 
cise on  occasion  may  find  it  difficult  or  impossible  to  rep- 
resentor describe  voluntarily  how  it  is  done,  and  on  the  other 
hand,  one  who  is  able  to  describe  the  movements  may  be 
unable  to  perform  them  successfully. 

It  is  well  known  that  a  child  who  can  laugh  or  cry 
perfectly  in  response  to  the  proper  stimulations  may  be 
unable  to  do  so  voluntarily.  The  same  truth  applies  to  a 
greater  or  less  extent  to  everything  that  the  child  does. 
He  may,  under  proper  conditions,  walk  or  stand  gracefully, 
but  not  be  able  to  do  so  voluntarily.  He  may  use  words 
correctly  when  there  is  the  usual  stimulus  for  their  use, 
but  be  unable  to  put  the  words  in  sentences  or  tell  what 
they  mean.  He  may  be  able  to  repeat  a  verse  or  a  selec- 
tion when  started  on  it,  but  not  have  power  to  think  of  it  at 
will.  For  this  reason  one  who  understands  grammar 
well  may  use  poor  language,  while  one  who  uses  good  lan- 
guage may  know  little  of  grammar. 


3IO 


GENETIC    PSYCHOLOGY 


Again,  one  who  can  form  appropriate  pictures  and  con- 
cepts in  response  to  the  words  of  a  poem  may  be  quite 
unequal  to  writing  such  a  poem.  One  who  is  able  to 
follow  accurately  a  course  of  reasoning  may  be  utterly 
unable  to  construct  a  similar  line  of  reasoning,  and  one 
who  can  respond  accurately  and  tactfully  to  moral  and 
social  situations  may  be  unable  to  state  the  rules  of  eti- 
quette and  the  principles  of  morality.  These  facts  make 
it  clear  why  there  is  such  a  difference  between  theoretical 
knowledge  and  practical  ability,  and  why,  as  one  college 
president  expressed  it,  "  college  students  simply  flounder  for 
about  two  years  after  they  get  out  of  college." 

In  many  processes  of  learning,  the  reversal  of  the  direc- 
tion of  excitation  between  higher  and  lower  centers  begins 
at  once,  so  that  the  process  of  voluntary  control  is  only  a 
little  behind  the  acquisition  of  sensory  motor  responses. 
Imitation  plays  a  large  part  in  this  reversal,  particularly 
in  the  transitions  from  immediate  sensory  motor  imitation 
to  the  delayed  and  ideational  forms  in  which  acts  are 
reproduced,  not  at  the  moment  when  seen,  but  some 
minutes,  hours,  or  days  later.  In  conscious  learning  the 
process  is  often  facilitated  by  alternating  the  sensory 
motor  imitation  with  the  ideational.  The  child  observes 
how  some  one  else  does  a  thing  and  tries  to  do  it  with  per- 
haps indifferent  success.  He  is  shown  again  and  repeats 
his  attempt  perhaps  more  successfully.  He  then  practices 
the  movement  without  a  preliminary  observation  of  the 
movement  as  made  by  some  one  else.  The  sensory  stimu- 
lus may,  however,  remain  for  some  time  the  most  effective 
means  of  securing  the  right  movement.  This  is  illustrated 
by  such  movements  as  are  made  in  gymnastic  exercises 


TYPES   OF   LEARNING   ACTIVITY 


311 


or  in  skating.  One  who  cannot  successfully  execute  them 
alone  may  be  able  to  do  so  when  he  has  the  stimulus  of 
perceiving  others  make  the  movements  in  the  correct  way. 
The  same  is  true  also  to  a  marked  extent  in  articulation 
and  in  singing. 

The  child's  imitative  and  playful  tendencies  lead  him 
to  effectively  reverse  the  process  of  learning  in  most  lines 
of  incidental  learning,  so  that  he  not  only  knows  how 
things  are  done,  but  can  do  them.  In  school,  however, 
where  the  process  of  learning  is  directed  by  others,  the 
reversal  often  fails  to  take  place.  Many  things  are  learned 
in  a  receptive  way,  and  the  teacher  is  then  surprised  that 
they  cannot  be  repeated  in  any  other  way  or,  in  the  case 
of  ideas  which  seem  to  be  understood,  that  they  cannot  be 
used  in  doing  things. 

It  is  well  recognized  that  in  the  trades  and  professions 
a  man  may  be  very  well  trained  theoretically  and  yet  be 
very  unsuccessful  in  actual  execution,  while  another  man 
may  have  no  theoretical  training  and  yet  be  very  success- 
ful in  practice.  The  first  has  had  the  higher  centers  trained 
to  respond  to  external  stimulations  and  to  impulses  coming 
from  each  other,  but  has  had  little  training  in  sending  im- 
pulses from  the  higher  to  the  lower  centers,  while  the  second 
has  had  much  training  in  sending  impulses  from  the 
higher  to  the  lower  centers  in  such  a  way  as  to  bring 
about  the  proper  adaptations  to  the  external  conditions. 

In  many  instances  success  depends  upon  general  direc- 
tion by  higher  centers  and  also  upon  quick  sensory  responses 
to  the  changing  situations.  In  other  words,  impulses 
constantly  passing  in  both  directions  must  be  coordinated 
in  order  that  ends  may  be  gained  in  practical  affairs,  in 


31- 


GENETIC    PSYCHOLOGY 


distinction  from  success  in  reaching  conclusions  in  cases 
theoretically  defined  and  supposedly  unchanging. 

Movements  may  be  the  result  of  sensory  motor  stimula- 
tion or  caused  by  impulses  sent  from  the  higher  centers 
to  the  lower.  The  same  is  true  of  all  forms  of  expression. 
They  may  be  called  forth  by  immediate  external  stimula- 
tion or  they  may  be  the  result  of  the  lower  centers  being 
stimulated  by  the  higher.  The  value  of  manual  training 
and  of  other  forms  of  expression,  in  learning,  is  not  because 
movements  are  made,  but  because  the  higher  centers  are 
gaining  power  to  stimulate  and  direct  the  activities  of  the 
lower.  This  is  also  the  psychological  justification  for  the 
general  principle  of  having  impression  followed  by  ex- 
pression. It  should  be  recognized,  however,  that  the  de- 
velopment of  the  higher  centers  is  greater  in  proportion 
as  the  mode  of  expression  is  different  from  that  of  the 
impression. 

The  higher  centers  may  become  capable  not  only  of 
reversing  the  course  of  impulses  so  that  a  person  may  do 
voluntarily  what  has  formerly  been  done  in  response  to 
external  stimulation,  but  they  may  stimulate  and  direct  the 
lower  centers  in  the  performance  of  activities  for  which 
they  have  had  no  direct  stimulus;  e.g.  an  oral  language 
is  usually  learned  through  the  sensory  stimulus  of  hearing 
that  language  spoken.  It  is  possible,  however,  for  an 
individual  to  learn  to  speak  a  foreign  language  from  the 
study  of  books.  By  means  of  free  images,  of  sounds  as- 
sociated with  certain  visual  symbols,  he  can  learn  in  a  rep- 
resentative way  the  combinations  of  sounds  constituting 
the  words  of  the  foreign  language.  He  can  then  give  the 
vocal  organs  practice  in  uttering  combinations  of  sounds 


TYPES    OF   LEARNING   ACTIVITY 


313 


that  they  have  never  had  any  sensory  stimuKis  to  utter. 
It  is  also  possible  to  learn  various  forms  of  gymnastic 
exercises  and  of  constructive  movements  by  reading  de- 
scriptions of  them  and  then  practicing  their  execution. 
Such  methods  of  learning  demonstrate  the  extraordinary 
power  of  the  higher  centers  over  the  lower  that  may  be 
developed.  It  should  be  remembered,  however,  that  the 
lower  centers  must  have  been  previously  well  trained  in 
some  respects  and  have  been  under  control  of  the  higher, 
or  such  acts  as  learning  new  movements  in  a  voluntary 
way  would  not  be  possible. 

In  this  learning  of  new  things  by  lower  centers  under 
the  direction  of  the  higher,  we  have  a  most  striking  differ- 
ence between  man  and  animals.  There  is  no  evidence 
whatever  that  higher  centers  ever  take  the  lead  in  the  learn- 
ing processes  of  animals.  Whatever  they  learn  to  do  is 
learned  through  external  stimulation,  either  from  their 
natural  environment  or  through  special  training  given  by 
man.  No  one  has  even  claimed  that  a  horse  ever  under- 
takes to  train  himself  to  be  a  good  trotter,  or  a  l^ird  a  good 
singer,  although  both  are  readily  subject  to  externally 
initiated  training  of  this  sort. 

In  the  case  of  man,  on  the  other  hand,  ideals  of  what  he 
wishes  to  be  are  among  the  most  important  sources  of  all 
learning  activity.  He  forms  ideals  and  then  directs  the  learn- 
ing processes  by  which  he  is  enabled  to  realize  those  ideals. 
In  doing  this  he  does  not  necessarily  proceed  by  the  method 
of  training  the  lower  centers  to  perform  activities  for  which 
they  have  previously  received  no  sensory  stimulus,  but  he 
frequently  takes  the  easier  and  more  economical  method 
of  seeking  opportunity  for  the  reception  of  the  proper  sen- 


314  GENETIC   PSYCHOLOGY 

sory  stimulations.  In  learning  a  language,  for  example, 
he  does  not  try  to  train  the  vocal  apparatus  wholly  by  means 
of  impulses  sent  from  the  higher  centers,  but  he  arranges 
to  be  with  people  who  speak  the  language,  and  thus  secures 
the  training  of  the  vocal  apparatus  through  the  much  more 
rapid  and  effective  means  of  sensory  motor  stimulation  and 
immediate  imitation.  What  is  true  of  language  is  true  in 
all  lines  of  learning.  The  most  effective  learning  is  under 
the  direction  of  the  higher  centers,  but  these  higher  centers 
often  accomplish  the  purposes  desired,  not  by  attempting 
to  directly  control  the  practice  activity  of  the  lower  centers, 
but  by  arranging  that  the  lower  centers  shall  have  a  suffi- 
cient amount  of  practice  in  the  simpler  process  of  respond- 
ing to  external  stimulation. 

SEPARATE    AND   COMBINATION    LEARNING 

Although  the  various  learning  processes  may  be  carried 
on  separately,  they  are  usually  combined  to  a  greater  or 
less  extent.  Frequently  one  process  dominates,  yet  is 
very  much  assisted  by  the  others.  When  a  number  of 
persons  are  listening  to  a  lecture  some  depend  upon  one 
and  some  upon  another  kind  of  mental  process  in  learning 
from  the  speaker.  A  stenographer  may  hear  the  words 
and  respond  to  each  by  making  the  proper  character,  with 
little  or  no  activity  of  the  representative  and  conceptual 
centers.  Another  individual  may  form  numerous  mental 
images  as  he  listens  to  the  speaker,  with  little  attention  to 
the  words  and  to  the  thought.  A  third  may  form  ideas 
almost  without  imagery  and  with  no  attention  to  the  exact 
words  used.     Afterward  the  stenographer  may  reproduce 


TYPES   OF   LEARNING   ACTIVITY  315 

the  words  of  the  lecture  with  great  accuracy  and  in  doing 
so  may,  at  the  same  time,  form  either  images  or  concepts 
associated  with  the  words.  The  one  who  formed  images 
in  the  first  place  may  translate  these  into  words  which 
may  be  quite  different  from  the  ones  used  by  the  speaker, 
and  in  doing  so  may  give  some  attention  to  the  thought 
connecting  these  images.  The  third  may  recall  the  line  of 
thought  pursued  by  the  speaker,  image  in  some  detail  the 
parts,  and  express  the  ideas  in  his  own  words. 

In  all  these  cases  each  person  seems  to  depend  largely 
upon  one  form  of  learning,  but  it  is  safe  to  say  that  in  nearly 
all  cases  the  other  forms  of  learning  play  a  more  or  less 
important  part.  The  stenographer  depends  chiefly  upon 
previous  training,  by  which  each  elementary  sound  has 
become  associated  with  a  definite  movement.  Since, 
however,  the  making  of  the  movement  does  not  imme- 
diately coincide  with  the  hearing  of  the  sound,  but  follows 
it  at  a  greater  or  less  distance,  he  is  carrying  in  mind  a 
number  of  sounds,  while  making  the  movements  in  re- 
sponse to  those  previously  heard.  If  he  has  mental  images 
or  concepts  corresponding  to  the  sounds  as  grouped  in 
phrases  and  sentences,  he  can  do  this  much  more  success- 
fully than  if  they  are  to  him  a  series  of  unrelated  and 
meaningless  words.  Without  exception,  stenographers 
can  take  more  accurately  a  series  of  sentences  expressing 
familiar  thought  than  they  can  either  isolated  words  or 
sentences  expressing  ideas  quite  unfamiliar  to  them.  A 
complete  sensory  motor  re])roduction  of  words  is,  however, 
possible  to  a  few  individuals.  A  most  remarkable  instance 
of  this  kind  is  related  by  a  missionary.  After  delivering 
an  address  to  the  nati\es  in  his  own  language,  he  noticed 


3l6  GENETIC   PSYCHOLOGY 

a  crowd  gathered  around  a  native  who  knew  nothing  of 
that  language.  The  man  who  was  speaking  to  them, 
so  far  as  the  missionary  was  able  to  determine,  reproduced 
accurately  every  word  and  gesture  that  he  himself  had  used 
in  his  address  shortly  before. 

In  the  case  of  the  one  who  relies  chiefly  upon  mental 
pictures,  success  depends  largely  upon  the  association 
which  he  has  previously  formed  of  words  and  the  images 
suggested  by  them,  but  much  assistance  is  derived  in  form- 
ing and  connecting  these  mental  pictures  from  his  under- 
standing of  the  general  line  of  thought  being  pursued.  He 
is  probably  also  assisted  in  many  cases  by  incipient  move- 
ments corresponding  to  actions  suggested  by  the  images. 

The  conceptual  learner,  although  depending  largely 
upon  the  abstract  ideas  suggested  by  the  words,  and  the 
relation  of  those  ideas  to  vvdiat  he  already  knows  of  the 
subject  being  discussed,  yet  is  also  often  greatly  assisted 
by  images  around  which  some  of  the  principal  ideas  are 
grouped  or  by  certain  word  symbols  under  which  he  groups 
the  different  thoughts  expressed.  In  many  cases  he  is 
able  to  recall  the  thought  either  by  reproducing  some  of  the 
images  called  up  by  the  speaker  and  then  expressing  the 
thought  associated  with  them,  or  by  reproducing  certain 
words  that  serve  as  an  outline  of  the  topics  treated.  In 
some  instances  a  sensory  motor  learning  of  such  an  outline 
may  be  used  as  a  means  of  recalling  the  thoughts  expressed. 
Some  persons  with  such  an  outline  may  reproduce  a  lecture 
with  great  accuracy  and  completeness,  while  without  it 
they  would  be  able  to  tell  little  or  nothing. 

The  same  combination  of  processes  takes  place  to  a 
greater  extent  than  has  just  been  described  in  nearly  all 


TYPES   OF   LEARNING   ACTIVITY  317 

instances  of  studying  lessons  and  learning  selections. 
In  learning  a  poem,  for  example,  one  may  learn  it  in  the 
sensory  motor  way,  being  helped  greatly  by  the  rhyme 
and  rhythm  but  incidentally  also  by  the  imagery  and  the 
thought.  Another  may  form  an  image  for  each  line  and 
associate  the  words  with  that  imagery,  while  a  third  may 
get  the  thought  of  the  different  lines  and  verses  in  relation 
to  the  thought  of  the  whole  and  then  associate  with  it  the 
words  expressing  the  thought.  In  many  cases  all  of  these 
processes  are  carried  on  at  once  without  any  one  of  them 
especially  predominating. 

Recent  experiments  in  memory,  in  which  the  mode  of 
memorizing  was  studied,  emphasized  the  fact  that  most 
individuals  have  some  kind  of  a  plan  or  habit  of  memoriz- 
ing and  often  make  use  of  some  form  of  imagery.  Im- 
provement in  memory  is  usually  the  result  either  of  greater 
facility  in  the  use  of  some  memory  scheme  or  the  adoption 
of  a  more  effective  scheme  of  memorizing.  A  detailed 
study  of  schema  used  in  learning  of  various  kinds  will  be 
likely  to  yield  important  results  for  psychology  and  ped- 
agogy. 

Most  things  that  a  child  learns  to  do  involve  activities 
of  both  higher  and  lower  centers  and  also  a  process  of 
getting  the  sensory  motor,  representative,  and  thinking 
activities  to  act  harmoniously.  In  learning  to  read,  for 
example,  the  child  is  acquiring  the  sensory  motor  process 
of  responding  to  a  visual  stiniulus  by  appropriate  move- 
ments of  the  vocal  organs.  It  is  possible  to  do  this  without 
forming  any  association  whatever  between  the  visual  sym- 
bols and  the  images  or  ideas  which  they  are  supposed  to 
suggest.     This  is  frequently  done  without  the  knowledge 


31 8  GENETIC    PSYCHOLOGY 

of  the  teacher,  especially  when  a  series  of  words  are  learned 
together  and  in  one  place  only.  Again,  a  child  who  does 
not  know  any  of  the  words  visually  but  who  knows  them 
auditorially,  may  at  sight  of  the  page  be  able  to  repeat 
every  word  on  it.  In  order  to  get  the  sensory  motor  con- 
nection between  each  visual  word  and  its  vocal  utterance, 
it  is  necessary  that  the  word  shall  be  seen  in  various  com- 
binations in  relation  to  other  words.  If  this  is  not  done 
the  association  may  be  chiefly  with  a  certain  place  in  the 
complex  percept  of  a  page,  paragraph,  or  sentence.  The 
association  between  the  oral  word  and  the  visual  word 
becomes  strong  just  in  proportion  as  the  connections  be- 
tween the  visual  word  and  its  immediate  accompaniments 
in  perception  are  broken  up  by  continual  variation  in  the 
associates  of  the  word. 

During  the  process  of  acquiring  the  sensory  motor  as- 
sociations the  attention  may  have  been  fully  occupied  with 
that  process  so  that  no  images  were  formed  even  in  the 
case  of  words  previously  familiar  in  their  auditory  form. 
If  such  is  the  case,  a  distinct  process  of  representative 
learning  is  necessary  so  that  the  visual  symbol  may  not 
only  call  up  the  auditory  symbols,  but  also  the  things 
symbolized. 

Again,  if  the  sensory  motor  and  representative  processes 
are  separately  acquired,  it  may  be  necessary  to  give  the 
child  special  training  in  getting  thought  from  the  series 
of  printed  symbols.  Even  in  cases  where  the  words  are 
all  familiar  and  call  up  appropriate  ideas,  he  may  not  con- 
nect them  in  such  a  way  as  to  get  the  thought  of  the  phrase, 
clause,  sentence,  or  paragraph  as  a  whole.  This  is  a  very 
common  condition  in  children  who  have  just  learned  to 


TYPES   OF   LEARNING   ACTIVITY  319 

read  by  the  method  of  learning  elements  separately.  They 
arc  frequently  unable  to  get  the  true  meaning  of  what  they 
have  read  without  their  attention  being  called  specifically 
to  the  relation  of  the  different  words  to  each  other. 

In  order  to  read  successfully,  all  of  these  processes  must 
be  carried  on  simultaneously  and  harmoniously.  It  fre- 
quently happens  that  a  child  who  knows  all  the  words  in  a 
sensory  motor  way  when  his  attention  is  directed  especially 
to  that  process,  miscalls  many  of  the  words  when  his 
attention  is  directed  to  the  images  or  meanings  suggested 
by  them. 

In  reading  aloud,  the  articulation  and  the  proper  em- 
phasis and  inflection  involve  a  still  further  complication 
of  processes ;  hence  a  child  who  is  able  to  get  thought  from 
silent  reading  may  be  unable  to  read  clearly  and  with 
proper  expression  while  getting  the  thought,  though  he 
may  be  able  to  do  so  in  imitation  of  another.  Again,  if 
his  attention  is  directed  to  articulation,  pauses,  and  em- 
phasis, he  may  be  unable  to  get  the  thought  which  should 
be  expressed. 

The  process  of  reading  aloud  correctly,  intelligently, 
and  expressively,  involves  the  harmonized  activity  of  a 
number  of  different  centers  at  several  levels,  in  a  manner 
comparable  to  and  very  much  more  complex  than  the 
working  of  belts,  w^heels,  cranks,  and  pulleys  in  any  ma- 
chine. As  in  the  case  of  the  machine,  parts  may  run  suc- 
cessfully alone  by  changes  of  adjustment,  or  a  defect  in 
one  part  may  interfere  with  the  working  of  all  the  other 
parts. 

The  process  of  learning  to  read  may  be  carried  on  in  an 
order  exactly  the  reverse  of  that  which  has  just  been  de- 


320  GENETIC   PSYCHOLOGY 

scribed.  Instead  of  acquiring  the  elementary  processes 
separately  at  first  and  then  their  proper  combination,  the 
complex  process  may  be  attended  to  first  and  the  elemen- 
tary process  learned  incidentally.  From  pictures,  explana- 
tions, or  talks  about  objects,  or  by  dramatic  representations, 
a  child  may  get  the  idea  of  the  thought  to  be  expressed 
and  then  begin  learning  the  visual  symbols  that  express 
that  thought.  His  knowledge  of  the  thought  to  be 
expressed,  and  his  mental  images  of  the  situations  in- 
volved, will  in  many  cases  enable  him,  by  the  help  of  his 
knowledge  of  oral  language,  to  guess  at  what  the  visual 
symbols  stand  for.  If  this  guessing  is  supplemented  and 
corrected  by  the  teacher,  the  attention  of  the  pupil  being 
directed  toward  the  peculiarities  of  the  visual  symbol  for 
each  word,  incidentally  and  without  withdrawing  it  from 
the  thought  being  expressed,  the  child  will  soon  form  the 
sensory  motor  associations  with  the  separate  words.  If 
the  thought  still  is  prominent  in  his  mind  as  he  utters  the 
words  of  the  sentence,  he  will  speak  them  with  something 
of  the  same  expression  that  he  already  uses  in  imparting 
his  own  ideas. 

In  this  method  of  learning  to  read,  thought  leads  and  the 
lower  centers  learn  under  the  direction  of  the  higher,  all 
the  processes  being  harmoniously  combined  while  each  is 
being  acquired.  In  order  to  learn  to  read  successfully 
in  this  way  the  child's  attention  must  be  kept  occupied 
more  or  less  with  interesting  thoughts  that  are  being  gained 
through  the  reading,  but  it  will  be  necessary  to  occasion- 
ally direct  his  attention  to  sensory  motor  activities  in  which 
he  shows  a  deficiency.  Sometimes  it  will  be  necessary 
to  give  special  drill  in  recognition  and  pronunciation  of 


TYPES   OF   LEARNING   ACTIVITY 


321 


words  and  of  elementary  sounds  aside  from  the  reading 
exercise.  Whether  the  method  of  acquiring  the  processes 
of  reading  separately,  beginning  with  the  lower  and  then 
learning  to  combine  all  of  them  after  the  higher  have  been 
acquired,  should  be  used,  rather  than  the  method  of  learn- 
ing all  the  processes  at  once,  with  the  higher  thought  process 
leading,  is  to  be  determined,  not  by  the  facility  with  which 
any  one  process  may  be  acquired,  and  the  degree  of  ac- 
curacy attained  at  any  particular  stage,  but  by  the  readiness 
and  completeness  with  which  all  of  the  processes  are  ulti- 
mately acquired.  In  practice,  a  single  child  may  be  taught 
more  successfully  by  the  thought  and  combination  method 
than  can  a  large  number,  because  one  can  be  sure  that  he  is 
looking  at  the  right  word. 

In  learning  to  write,  there  is  a  similar  combination  of 
complex  processes,  but  directed  more  toward  the  expression 
than  the  acquisition  of  thought.  Much  more  sensory 
motor  practice  is  necessary  in  learning  to  write  than  in 
learning  to  read,  because  the  vocal  organs  have  already 
been  more  completely  trained  for  the  utterance  of  sounds 
than  has  the  hand  in  the  making  of  forms.  The  repre- 
sentative process  is  also  more  important  in  learning  to 
write  because  the  child,  after  his  first  attempt  at  copying, 
must  be  able  to  form  an  image  of  the  letters  to  be  made, 
and  he  must  also  remember  the  way  in  which  these  letters 
are  combined  to  form  the  words  that  he  wishes  to  use.  It 
is  therefore  much  more  difficult  to  teach  a  child  to  express 
thought  in  writing  by  the  combined  method,  with  the 
thought  to  be  expressed  leading  and  directing  the  represen- 
tative and  sensory  motor  processes,  than  it  is  to  pursue 
the  same  method  in  accjuiring  ability  to  gain  thought  from 
y 


322  GENETIC   PSYCHOLOGY 

the  printed  page.  Some  special  drill  is  usually  necessary 
upon  the  motor  process  of  writing  and  the  memory  process 
of  spelling,  but  if  these  processes  are  carried  on  entirely 
without  connection  with  the  expression  of  thought  in  writ- 
ing, the  child  is  liable  not  to  combine  the  processes  already 
acquired  with  the  thought  process,  but  to  spell  incorrectly 
words  that  he  knows  orally  and  to  use  quite  a  different 
style  of  penmanship  when  expressing  thought  from  that 
used  in  the  copy  book. 

In  arithmetic,  the  child  must  acquire  sensory  motor, 
representative,  and  conceptual  facility  in  order  to  do  his 
work  successfully.  The  number  symbols,  either  auditory 
or  visual,  may  be  acquired  either  singly  or  in  their  various 
combinations  in  a  purely  sensory  motor  way.  A  child 
who  knows  nothing  whatever  about  numbers  may  learn 
a  large  section  of  the  multiplication  table  in  a  short  time, 
especially  if  it  is  arranged  so  there  is  some  rhythm  in  speak- 
ing the  numbers.  Much  of  the  learning  of  the  multipli- 
cation table  in  school  is,  unknown  to  the  teacher,  of  this 
sensory  motor  type.  Acquisition  is  made  in  this  w^ay  most 
readily  when  the  numbers  are  given  in  the  same  order  every 
time.  After  they  have  been  learned  in  this  way  the  series 
may  be  broken  up  and  the  separate  combinations  acquired. 
In  the  process  of  breaking  up  the  series  the  child  usually 
acquires  images  of  the  separate  symbols,  and  when  two 
terms  of  a  combination  are  given  with  the  proper  signs,  as 
3  X  4,  he  forms  an  image  of  the  third  number  either  as 
heard  or  seen,  or  both,  according  to  his  previous  training. 
Tables  thus  learned  may  then  be  used  in  the  solution  of 
problems. 

The  ordinary  working  of  examples  may  be  and  often  is 


TYPES   OF   LEARNING   ACTIVITY  323 

little  more  than  a  sensory  motor  and  representative  dealing 
with  symbols  in  ways  that  have  been  acquired  by  imitation 
and  direction.  The  symbols  may  not  arouse  any  repre- 
sentation of  groups  of  objects,  or  any  concept  of  number 
relations.  It  is  quite  common  for  children  to  think  it 
utterly  impossible  to  perform  the  operation  of  subtraction 
when  the  subtrahend  is  placed  above  the  minuend,  or  to 
work  an  example  in  long  division  if  the  mode  of  expressing 
it  is  changed.  The  process  is  to  them  wholly  one  of  manip- 
ulating symbols.  Later  they  may  acquire  more  complete 
number  concepts  and  be  conscious  of  the  fact  that  in  thus 
manipulating  symbols  they  are  .representing  number  rela- 
tions. The  importance  of  sensory  motor  familiarity  with 
symbols  used  in  arithmetical  calculations  w^ill  be  impressed 
upon  any  one  who  tries  to  multiply  LXV  by  XXXII,  using 
Roman  numerals  exclusively. 

Before  going  to  school  the  child  usually  acquires  first 
the  auditory  symbols  that  stand  for  number  ideas  and 
knows  that  series  in  order,  to  ten  or  perhaps  a  hundred. 
He  may  also  be  able  to  apply  the  series  to  objects  in 
counting  them.  When  learning  to  count,  the  child  is 
likely  to  take  the  number  as  the  specific  name  for  the 
object  pointed  out  when  the  number  is  spoken,  e.g.  the 
forefinger  as  having  the  name  "one"  and  the  little 
finger  that  of  "  four,"  but  from  hearing  the  number 
symbol  applied  to  various  objects  in  various  combi- 
nations, he  is  enabled  to  pick  out  the  number  charac- 
teristic of  objects  from  the  many  that  they  possess.  This 
is  the  beginning  of  the  number  concept.  This  concept 
becomes  more  and  more  definite  with  his  increase  in  abil- 
ity to  represent  the  number  of  objects  indicated  by  each 


324  GENETIC   PSYCHOLOGY 

symbol,  when  they  are  not  present,  and  by  his  ability  to 
represent  the  various  combinations  of  smaller  groups  of 
objects  that  go  to  make  up  the  larger  groups.  The  child 
has  some  knowledge  of  "twenty"  when  he  knows  that  it 
comes  some  distance  along  in  the  number  series,  and  when 
he  knows  that  it  means  a  larger  group  of  objects  than  ten, 
and  that  it  comes  earlier  in  the  series  than  fifty  and  stands 
for  a  smaller  group  of  objects.  In  acquiring  what  are 
called  the  facts  of  number  he  may  get  exact  ideas  of  the 
relation  of  twenty  to  smaller  and  larger  numbers.  The 
process  of  getting  definite  ideas  of  numbers  so  that  he 
knows  just  how  much  larger  one  is  than  another,  is  greatly 
facilitated  by  the  various  combinations  of  objects  that  may 
be  used,  but  number  ideas  grow  slowly,  especially  when  the 
attention  is  much  occupied  with  symbols  and  processes. 
Not  unfrequently  drill  on  processes  checks  entirely  the 
growth  of  number  concepts. 

After  considerable  experience  in  applying  the  proper 
symbol  to  small  groups  of  objects  and  learning  the  sym- 
bols expressing  the  combination  of  groups  into  other  groups, 
the  sensory  motor  process  may  give  place  to  the  process 
of  imaging  objects.  Later  definite  representation  is  un- 
necessary and  concepts  of  numbers  and  their  combinations 
indicated  by  symbols  may  be  substituted  for  the  longer 
process  of  imaging  objects  in  groups.  When  this  stage 
has  been  reached,  further  progress  in  number  may  be  made 
with  only  occasional  returns  to  actual  imaging  of  objects 
or  sensory  experience  with  them.  A  knowledge  of  place 
in  the  number  symbol  series  and  the  facts  regarding  the 
simple  combinations  are  now  of  great  help  in  acquiring 
the  larger  combinations  and  may  profitably  be  used  instead 
of  manipulating  objects. 


TYPES   OF   LEARNING   ACTIVITY  325 

The  simplest  stej)  in  making  use  of  the  number  series 
in  learning  the  facts  of  number  is  taken  when  the  child 
learns  to  omit  every  other  one  of  the  series,  or  in  other 
words,  learns  to  count  by  twos.  Further  progress  is  made 
in  learning  to  omit  every  other  one  of  the  two  scries,  or  in 
other  words,  learning  to  count  by  fours.  Another  process 
that  may  come  as  early  or  earlier  is  that  of  learning  to 
count  by  tens,  twenties,  etc.,  a  process  very  similar  to  that 
of  counting  by  ones.  This  is  easily  followed  by  learning 
to  count  by  fives.  By  counting  forward  and  backward 
and  by  noting  how  many  times  the  given  number  was 
used  in  counting  in  each  direction,  the  facts  of  subtraction, 
multiplication,  and  division  that  are  necessary  to  the  more 
complete  and  accurate  concept  of  the  various  numbers, 
are  readily  acquired. 

After  learning  to  count  by  twos  beginning  with  one,  a 
child  can  soon  count  by  threes  by  adding  two  and  one  to 
each  sum.  Counting  by  six  and  by  eight  is  also  easy  to 
one  who  counts  readily  by  threes  and  fours.  All  other 
simple  number  combinations  can  easily  be  acquired  by 
one  who  is  familiar  with  those  previously  mentioned,  e.g. 
seven  plus  eight  may  be  thought  of  as  one  less  than  eight 
and  eight.  In  this  way  each  new  fact  is  not  separately 
memorized  but  recognized  by  means  of  what  is  already 
known.  A  child  who  counts  on  his  fingers  has  a  sensory 
motor  series  that  is  better  for  him  to  apply  than  to  simply 
learn  the  answer  given  him,  but  the  one  who  has  a  few 
combinations  well  learned  can  apply  his  representative 
and  conceptual  series  in  determining  new  combinations 
with  much  greater  rapidity. 

In  all  learning,  but  especially  in  that  of  mathematics. 


326  GENETIC    PSYCHOLOGY 

some  sort  of  schematic  arrangement  of  what  has  been 
learned  may  be  used  as  a  test  for  each  new  thing.  This 
mode  of  testing  and  grouping  should  change  in  content 
and  form  as  one's  acquisitions  become  more  extensive  and  ^ 
of  higher  forms.  For  example,  formulas  and  equations 
are  necessary  in  higher  mathematics.  It  is  probable  that 
many  persons  never  get  beyond  the  "finger  counting" 
stage  of  testing  and  learning  not  only  in  mathematics 
but  in  many  lines  of  thought. 

The  importance  of  fixed  "standards"  or  schema  with 
which  varied  phenomena  of  the  same  general  kind  can 
be  compared  can  scarcely  be  overestimated  in  considering 
mental  development.  The  original  standards  for  exten- 
sion, "span,"  "cubit,"  like  the  first  standard  counting 
series,  are  based  upon  human  anatomy,  while  the  original 
time  measurements  are  based  upon  the  "winking  of  an 
eye"  and  common  phenomena  of  day  and  night,  change  of 
moon  and  of  seasons.  History  is  possible  only  when  a 
definite  unit  and  a  point  of  reckoning  are  fixed.  No  ac- 
curate development  of  industries  or  science  is  possible 
without  definite  standards  of  measurement  of  space,  time, 
force,  value,  etc.  This  has  long  been  recognized  in  the 
sciences  and  the  industries,  but  the  importance  of  standards 
of  reference  in  mental  development  has  only  begun  to  be 
appreciated.  There  is  good  reason  for  believing  that  the 
superior  mental  development  of  man  is  in  part  due  to  his 
use  of  mental  standards.  Some  of  the  earlier  standards 
to  be  formed  are  those  of  size  and  shape.  Appearances 
of  objects  differ  infinitely  according  to  distance  and  point 
of  view,  but  we  adopt  the  position  and  distance  that 
give  us  the  clearest  and  most  easily  attained  view,  i.e.  at 


TYPES   OF   LEARNING   ACTIVITY  327 

right  angles  to  the  line  of  sight  and  usually  at  a  distance 
of  about  a  foot,  where  they  can  be  best  seen  and  easily 
handled.  Every  geometrical  figure  is  judged  by  how  it 
would  look  if  brought  to  that  position  rather  than  by  its 
particular  appearance  at  the  moment.  Every  class  of 
objects  comes  to  have  a  standard  appearance  according  to 
the  appearance  that  is  oftcnest  and  most  clearly  presented. 

Words  and  symbols  of  all  kinds  also  serve  as  standards 
of  experiences.  The  importance  of  standards  of  measure- 
ment is  appreciated  when  one  attempts  to  estimate  distance 
in  unfamiliar  units,  e.g.  centimeters.  One  who  has  es- 
timated larger  distances  in  yards  may  even  find  it  hard 
to  do  so  in  rods  or  feet. 

In  music  the  notes  and  their  arrangement  in  a  scale  must 
be  learned  as  a  standard  before  progress  in  the  science  of 
music  is  possible.  In  physics,  units  of  weight,  force,  etc., 
are  necessary  to  clear  conception,  and  in  every  sphere  of 
knowledge  definitions,  formulas,  and  general  truths  must 
be  acquired  before  accurate  conceptual  thinking  can  be 
carried  on.  The  standards  may  differ  greatly  for  different 
things  in  the  same  individual,  but  whatever  kind  of  stand- 
ard is  most  frequently  used  indicates  whether  one  is  domi- 
nantly  of  the  sensory  motor,  representative,  or  conceptual 
type  of  intelligence. 

In  concluding  the  topic  of  learning  it  may  be  emphasized 
that  practically  everything  that  is  learned  consists,  if  we 
analyze  it,  of  many  simpler  processes  and  usually  of  series 
not  only  of  different  sense  elements  but  of  series  of  activ- 
ities at  several  different  levels.  It  is  only  when  these  series 
are  properly  linked  together  and  adjusted  to  each  other 
that  success  is  possible.     It  is  not  enough  that  any  or  all 


328  GENETIC    PSYCHOLOGY 

of  the  scries  of  activities  be  acc}uired  separately,  but  each 
must  be  brought  into  such  relation  with  all  the  others  that 
its  performance  facilitates  rather  than  interferes  with  their 
performance.  It  is  possible  to  acquire  the  different  series 
separately  or  all  together,  but  an  intermediate  course  is 
probably  often  most  economical,  some  elementary  series 
being  acquired  alone  or  in  combination  with  others,  then 
the  process  complicated  by  the  addition  of  other  series. 
As  new  skill  and  knowledge  are  acquired,  one  series  then 
another  leads  or  is  used  as  a  standard  of  reference. 

Sensory  motor  standards  are  common  in  the  earlier 
stages,  while  later  representative  and  conceptual  standards 
are  most  used. 

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♦Arnold,  Felix.    The  Initial  Tendency  in  Ideal  Revival,  Am.  Jr. 

Psych.,  Vol.  XVIII,  pp.  239-252. 
Bergstrom,  J.  A.   An  Experimental  Study  of  Some  of  the  Conditions 

of  Mental  Activity,  Am.  Jr.  Psych.,  Vol.  VI,  pp.  246-274. 
*Browne,  Chas.  E.     The  Psychology  of  Simple  Arithmetical  Pro- 
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the  Telegraphic  Language,  Psych.  Rev.,  Vol.  IV,  pp.  27-53. 
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TYPES   OF  LEARNING   ACTIVITY  329 

♦Ellison.  Children's  Capacity  for  Abstract  Thought,  Am.  Jr. 
Psych.,  Vol.  XIX,  pp.  253-260. 

Freeman,  F.  M.  Preliminary  Experiments  on  Writing  Reactions, 
Psych.  Rev.,  Monograph  Supp.,  No.  34,  1907,  pp.  311-333. 

♦French,  F.  C.  Mental  Imagery  of  Students,  Psych.  Rev.,  Vol.  IX, 
pp.  40-56. 

*Gard,  W.  L.  a  Preliminary  Study  of  the  Psychology  of  Reasoning, 
Am.  Jr.  Psych.,  Vol.  XVIII,  pp.  490-504. 

Gesell,  a.  L.  Accuracy  in  Handwriting  as  Related  to  School  In- 
telligence and  Sex,  Am.  Jr.  Psych.,  Vol.  XVII,  pp.  394-405. 

Hall,  G.  S.     Adolescence,  Chapter  III. 

*HuEY,  E.  B.     Psychology  and  Pedagogy  of  Reading. 

Jacobi,  Mary  P.  Psychological  Notes  on  Primary  Education  and 
the  Study  of  Language. 

*KuHXMAN,  F.  On  the  Analysis  of  the  Memory  Consciousness  for 
Pictures  of  Familiar  Objects,  Am.  Jr.  Psych.,  Vol.  XVIII,  pp. 
389-480. 

On  the  Analysis  of  the   Memory  Consciousness,  Psych.  Rev., 

Vol.  XIII,  pp.  316-347- 

Leuba  and  Hyde.  An  Experiment  in  Learning  to  make  Head  Move- 
ments, Vol.  XII,  pp.  351-360. 

Mach,  E.  On  the  Part  Played  by  Accident  in  Invention  and  Dis- 
covery, Monist,  Vol.  VI,  pp.  161-175. 

♦Meyerhardt,  M.  W.  Economical  Learning,  Ped.  Sem.,  Vol. 
XIII,  pp.  145-184- 

Morgan,  C.  L.     Comparative  Psychology,  Chapter  XII. 

QuANTZ,  J.  O.  Psychology  of  Reading,  Monograph  Supp.,  Vol. 
II,  No.  I,  December,  1897. 

♦Peterson,  H.  A.  Correlation  of  Certain  Mental  Traits  in  Normal 
School  Students,  Psych.  Rev.,  Vol.  XV,  pp.  322-338. 

Phillips,  D.  E.  Number  and  its  Applications  Psychologically 
Considered,  Ped.  Scm.,  Vol.  V,  pp.  221-279. 

♦Slack,  M.  Mirror  Writing  and  Left-Handedness,  Ped.  Scm.,  Vol. 
II,  pp.  236-244. 

Smedley,  F.  W.  Child  Study.  Report  No.  3,  of  the  Child  Study 
Department  of  the  Public  Schools  of  Chicago. 


330  GENETIC    PSYCHOLOGY 

Smith,  M.  K.  Reading  and  Memorizing  of  Meaningless  Syllables 
Presented  at  Irregular  Time  Intervals,  Am.  Jr.  Psych.,  Vol. 
XVIII,  pp.  504-513- 

Smith,  W.  G.  The  Relation  of  Attention  to  Memory,  Mind, 
January,  1895,  PP-  47-73- 

*SwiFT,  E.  J.     Mind  in  the  Making,  Chapter  VI. 

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307-373- 
Thorndike,  E.  L.     Memory  for  Paired  Associates,  Psych.  Rev., 
Vol.  XV,  pp.  122-138. 


CHAPTER  XI 

RACIAL  AND   INDIVIDUAL  DEVELOPMENT 

GENERAL   THEORY   AND    PRINCIPLES 

In  order  to  get  a  better  conception  of  the  genesis  of 
behavior  and  of  consciousness  in  the  race  and  in  the  in- 
dividual, and  to  better  understand  the  influences  affecting 
the  consciousness  of  individual  human  beings,  it  is  nec- 
essary to  take  a  survey  of  evolutionary  processes  from  a 
new  point  of  view,  i.e.  considering  the  elements  of  which 
organisms  are  composed  and  their  relation  to  each  other 
and  to  the  external  environment. 

The  lowest  form  of  animal  life  consists  of  a  single  cell, 
while  the  higher  forms  are  composed  of  billions  of  cells. 
The  germ,  however,  from  which  an  individual  of  the 
higher  forms  of  life  develops,  consists  of  a  single  cell.  This 
simple,  almost  microscopic  cell  develops  into  a  many  celled, 
complex  organism.  Evolutionary  theory  supposes  that 
in  racial  development  there  has  been  a  similar  change  of 
simpler  organisms  into  those  of  higher  and  higher  forms. 
In  the  case  of  the  individual  this  change  takes  place  in  a 
very  short  time,  ranging  from  hours  to  years,  while  in  the 
race  the  time  required  for  such  changes  varies  from  thou- 
sands to  millions  of  years.  The  development  in  the  race 
is  known  as  phylogeny  and  that  of  the  individual  as 
ontogeny. 

Since  both  phylogenetic  and  ontogenetic  development 

33^ 


?>2>^ 


GENETIC   PSYCHOLOGY 


is  from  very  simple  lo  very  complex  forms,  there  must 
necessarily  be  some  similarity  in  the  changes  that  take 
place.  As  a  matter  of  chance  it  would  be  expected  that 
a  human  organism,  which  begins  as  a  single  cell,  would 
at  a  certain  early  stage  of  development  show  some  simi- 
larity to  lower  forms  of  animal  life,  such  as  the  worm  or 
fish.  Many  such  resemblances  have  been  found ;  so  many, 
that  a  biogenetic  law  has  been  formulated  which  asserts 
that  the  individual  organism,  in  its  short  period  of  develop- 
ment, goes  through  all  the  chief  stages  of  development 
of  the  race  as  shown  in  the  different  forms  of  animal  life. 
The  human  embryo  is  not  only  not  distinguishable 
from  the  embryos  of  other  vertebrates  at  the  beginning, 
but  it  resembles  in  its  general  form  and  prominence  of 
parts  successively  higher  orders  of  animal  life  until  it 
assumes  the  typically  human  form.  In  building  up  the 
human  form,  the  most  obvious  and  direct  mode  of  con- 
struction from  the  original  germ  cell  does  not  seem  to  be 
taken,  but  the  development  proceeds  as  if  an  animal  of 
one  of  the  lower  forms  were  to  be  produced  and  then 
another  a  little  higher,  until  by  a  very  indirect  course  of 
development  the  human  form  is  finally  evolved.  Many 
extra  organs,  not  ordinarily  possessed  by  man,  such  as 
gill  slits,  a  tail,  and  extra  mammary  glands,  are  always 
found  in  the  embryo  of  man  and  all  mammals,  and  are 
occasionally  found  in  human  beings  at  birth.  By  the 
discovery  of  a  large  number  of  such  organs  that  are  prom- 
inent in  the  embryo  of  man  and  either  rudimentary  or 
entirely  absent  at  birth,  a  strong  case  has  apparently  been 
made  out  for  the  theory  that  the  germ  cells  of  the  race  have 
formed  a  habit  of  developing  in  certain  ways  that  persist 


RACIAL  AND   INDIVIDUAL   DEVELOPMENT         333 

in  spite  of  the  fact  that  the  method  is  indirect  and  un- 
economical. 

The  law  is  recognized  in  studying  the  relationship  of 
one  species  of  animals  to  another.  If  there  is  marked 
similarity  in  embryological  development,  the  fact  is  taken 
as  one  line  of  evidence  of  relationship,  though  no  biologist 
relies  exclusively,  and  some  rely  to  only  a  slight  extent, 
upon  such  similarity  in  determining  the  question  of  com- 
mon ancestry  of  various  species  of  animals. 

A  great  many  exceptions  have  been  found  to  this  bio- 
genetic law.  Some  stages  of  development  that  are  present 
in  lower  forms  are  omitted  in  the  higher,  and  the  order  of 
development  of  parts  is  not  always  the  same  in  the  higher 
as  it  is  in  the  lower.  A  still  more  striking  fact  has  been 
noted  that  in  the  development  of  the  lower  forms  certain 
organs  are  sometimes  much  more  prominent  in  the  embryo 
than  they  are  in  the  mature  animal,  just  as  if  the  embryo 
had  started  to  become  a  creature  of  a  higher  species,  with 
certain  organs  more  prominent  than  in  its  own  species. 
Such  facts  as  these  surely  cannot  be  explained  by  the 
theory  that  the  germ  cells  have  got  into  a  habit  of  develop- 
ing in  a  certain  way  unless  it  be  supposed  that  the  creature 
in  question  was  originally  of  a  higher  form  and  has  fallen 
back  into  a  lower.  It  is  now  believed  that  some  of  these 
organs  that  are  prominent  in  the  embryo  perform  needed 
functions  at  that  time  and  hence  are  not  the  useless  vestigial 
organs  that  they  have  been  supposed  to  be,  e.g.  the  pituitary 
body  in  the  brain. 

Aside  from  this  a  general  explanation  may  be  given  that 
will  more  satisfactorily  account  for  both  kinds  of  facts. 
Each  germ  cell   may  be  supposed  to  have  within  itself 


334  GENETIC   PSYCHOLOGY 

certain  special  growth  tendencies  that  cause  it  to  assume 
the  form  of  its  species  rather  than  that  of  any  other  species. 
This  special  growth  tendency  possessed  by  each  germ  cell 
may  not  be  absolutely  fixed  in  its  character  but  subject 
to  slight  variations  similar  to  the  trial  movements  of  organ- 
isms. The  germ  cells  of  different  orders  of  animal  life 
have,  to  a  considerable  extent,  different  growth  tendencies, 
although  there  are  some  common  elements  in  all.  In  the 
case  of  those  species  that  are  more  nearly  related,  a  greater 
similarity  in  growth  tendencies  would  naturally  exist. 
In  the  case  of  a  species  of  animal  descended  from  a  more 
primitive  form,  it  would  be  expected  that  some  of  the  growth 
tendencies  would  be  the  same,  but  that  others  would  have 
been  suppressed  and  still  others  made  more  prominent 
in  the  germ  cells  of  later  and  higher  forms.  In  this  way 
the  similarity  of  and  also  the  difference  between  phylo- 
genetic  and  ontogenetic  development  may  be  explained 
without  supposing  that  the  germ  cells  have  formed  a  habit 
of  developing  in  a  certain  way,  but  merely  that  certain  of 
their  somewhat  diverse  growth  tendencies  have  been 
suppressed  and  others  increased  by  the  influence  of  the 
environment  on  the  body  cells  and  indirectly  upon  the 
germ  cells  of  which  the  body  cells  are  the  environment. 

Plants  and  some  animals  may  be  propagated  by  cuttings, 
and  reproductive  cells  may  be  regarded  as  simply  parts 
of  the  original  organisms,  hence  the  development  of  an  in- 
dividual organism  is  a  development  of  the  same  general 
type  of  organization  as  that  of  the  species  and  we  should 
expect  a  similar  kind  and  order  of  development  of  the  in- 
dividual and  the  species.  WTiatever  differences  there  may 
be  in  the  two  cases  would  be  due  to  difference  in  infiuences 


RACIAL   AND   INDIVIDUAL   DEVELOPMENT         335 

affecting  development.  The  development  of  the  individual 
takes  place  in  response  to  the  direct  influence  of  the  environ- 
ment, the  influence  of  which  upon  the  species  is  indirect, 
through  the  reproductive  cells  that  survive  and  pass  on 
the  original  and  perhaps  also  some  of  the  acquired  charac- 
teristics of  the  species  from  one  generation  to  another. 
There  is  no  doubt  that  the  species  may  develop  in  a  certain 
direction  through  natural  and  artificial  selection  of  in- 
dividuals whose  reproductive  cells  are  to  produce  the  next 
generation.  The  question  most  in  dispute  is  whether 
evolution  in  the  species  can  take  place  in  any  other  way 
than  by  increasing  some  of  the  original  characteristics  of 
the  species  and  decreasing  others  through  natural  selection 
of  individuals.  It  has  been  held  that  the  changes  produced 
by  the  experience  of  the  individual  from  which  the  repro- 
ductive cell  comes,  are  imparted  to  the  reproductive  cell 
and  may  thus  become  established  in  the  species.  This  sup- 
position has  been  shown  to  be  almost  if  not  entirely  un- 
tenable in  so  far  as  it  supposes  that  the  specific  modifications 
produced  in  the  individual  are  imparted  to  the  reproductive 
cells. 

It  is  known  that  reproductive  cells  in  some  animals,  and 
probably  in  all,  are  at  an  early  stage  of  embryonic  de- 
velopment separated  from  those  which  develop  into  the 
main  body  of  the  individual.  These  cells  are  therefore 
almost  entirely  cut  off  from  the  influence  of  external  en- 
vironment. Their  real  environment  consists  of  the  body 
cells  and  it  is  quite  reasonable  to  suppose  that  changes  in 
that  environment  may  produce  changes  in  them;  but  it 
does  not  follow  that  the  change  is  of  the  same  character  as 
that  taking  place  in  the  body  cells.     Since  there  is  no 


336  GENETIC   PSYCHOLOGY 

nervous  connection,  the  chief  medium  for  the  transmission 
of  modifications  is  the  blood.  This  and  the  variations 
in  temperature  of  the  body  and  the  pressure  of  its  cells, 
must  be  the  chief  influences  tending  to  modify  the  repro- 
ductive cells  so  long  as  they  remain  in  the  body  of  the 
parent.  It  should  be  remembered  that  reproductive 
cells  while  in  the  body  of  the  separate  parents  are  not 
developing  very  much,  and  hence  are  probably  less  modifi- 
able than  where  greater  changes  are  taking  place. 

After  two  reproductive  cells  have  united  to  form  the  germ 
cell  from  which  an  individual  of  the  next  generation  is  to 
be  developed,  development  is  very  rapid  and  it  is  to  be 
expected  that  considerable  modifications  in  development 
may  be  produced.  Experiments  show  that  in  the  lower  ani- 
mals profound  modifications  may  be  produced  by  changes 
in  gravity,  temperature  and  food.  The  size,  coloring,  etc. 
of  butterflies  and  even  birds  may  be  thus  greatly  changed. 
It  is  probable  that  in  human  beings  and  other  of  the  higher 
animals  the  development  of  the  embryo  is  affected  by  the 
condition  of  the  mother.  In  human  beings  it  is  well 
known  that  the  presence  of  the  embryo  modifies  all  the 
physiological  processes  of  the  mother,  and  it  is  reasonable 
to  suppose  that  reciprocally  the  physiological  condition 
of  the  mother  modifies  the  development  of  the  embryo. 
Again,  before  reproductive  cells  have  been  united  we  know 
that  they  must  influence  the  development  of  the  body  cells, 
since  unsexing  greatly  modifies  development,  causing  the 
male  to  become  more  feminine  in  appearance  and  the 
female  more  masculine.  In  view  of  these  facts  it  is  not 
improbable  that  body  cells  modify  reproductive  cells  to 
some  extent  though  probably  not  to  nearly  as  great  an 


RACIAL   AND    INDIVIDUAL   DEVELOPMENT         337 

extent  as  the  rapidly  developing  embryonic  cells  are  affected 
by  the  body  cells  of  the  mother.  It  does  not  follow,  how- 
ever, that  the  modifications  are  of  the  same  kind  as  those 
that  occur  in  the  body  cells,  nor  is  it  certain  that  the  modi- 
fications that  do  take  place  extend  in  any  considerable 
degree  beyond  the  individual  in  whose  germ  cell  they 
occurred.  It  has  not  yet  been  proved  that  the  changes 
produced  by  unusual  temperature,  in  the  color  of  butter- 
flies' wings  and  birds'  feathers,  are  transmitted  to  the  next 
generation.  McDougall,  however,  found  that  substances 
injected  into  the  ovum  of  a  plant  may  not  only  cause  the 
seed  to  produce  a  plant  individually  different  from  the 
species,  but  that  its  descendants  also  have  the  new  char- 
acteristics. 

In  the  light  of  these  facts  it  would  seem  probable  that 
although  the  reproductive  cells  are  not  directly  affected 
by  the  external  environment,  they  may  be  modified  to  some 
extent  by  the  modifications  that  are  produced  by  the  en- 
vironment or  otherwise  in  the  body  cells,  and  that  some 
modifications  thus  produced  may  become  inheritable  char- 
acteristics in  the  species.  Where  the  environment  and 
mode  of  life  of  a  species  for  many  generations  develops 
in  the  life  of  each  individual  certain  characteristics  and 
suppresses  others,  it  is  most  probable  that  the  reproductive 
cells  will  be  modified  by  their  constant  environment  of 
changed  body  cells,  but  it  is  doubtful  to  what  extent  the 
characteristics  of  the  species  are  thus  permanently  changed. 
Plants  grown  for  many  generations  in  new  soil  and  climate 
show  modification  in  growth  tendencies  for  a  few  genera- 
tions when  brought  back  to  their  native  habitat.  We  are 
not  sure,  however,  as  to  how  permanent  such  modifications 
z 


338  GENETIC   PSYCHOLOGY 

arc.  Neither  can  we  say  how  far  the  modification  is  due 
to  the  selection  of  individuals  for  reproduction  by  man, 
and  how  far  characteristics  of  the  reproductive  cells  are 
increased  and  others  decreased  by  the  changed  external 
and  body  cell  environment. 

The  discussion  regarding  the  possibility  of  inheritance 
of  acquired  characteristics  carried  on  so  hotly  for  many 
years  will  probably  be  settled  by  experimental  zoology 
wholly  in  favor  of  neither  Weismann  nor  Lamarck,  by 
proving  that  modifications  may  be  produced  in  reproduc- 
tive cells  by  changes  in  body  cells,  but  that  the  changes 
in  body  cells  produced  by  experience  do  not  necessarily, 
and  probably  not  in  general,  produce  exactly  the  same  kind 
of  changes  in  the  reproductive  cells  and  the  individuals 
that  develop  from  them.  It  will  probably  also  be  estab- 
lished that  although  there  is  no  complete  and  rigid  deter- 
mination of  the  course  of  evolution  by  the  characteristics 
of  the  reproductive  cells,  yet  that  these  characteristics  are 
relatively  permanent  as  compared  with  those  of  body 
cells.  Since  variations  are  most  prominent  in  cross  breed- 
ing, it  is  probable  that  the  growth  tendencies  of  one  parent 
will  conflict  with  some  and  harmonize  with  other  growth 
tendencies  of  the  other  parent  cell.  The  result  is  that 
some  characteristics  are  increased  and  others  decreased, 
and  it  may  be  that  wholly  new  ones  may  thus  result  in 
somewhat  the  same  way  as  is  the  case  when  two  chemical 
molecules  unite.  A  changed  environment  may  favor 
such  variations  and  thus  help  to  produce  mutations  which 
are  the  result  of  changes  in  growth  tendencies,  while  grad- 
ual increase  and  decrease  of  characteristics  would  usually 
be  the  result  of  harmony  of  growth  tendencies  in  the  slightly 
different  cells  of  the  two  parents. 


RACIAL   AND    INDIVIDUAL    DEVKLOPMENT 


339 


Variations,  however  produced,  are  at  once  acted  u[)on  by 
natural  selection,  which  eliminates  individuals  with  char- 
acteristics least  favorable  to  survival  in  a  given  environ- 
ment. Temporary  lack  of  correlation,  however,  between 
variations  may  be  bridged  over  by  modification  in  the 
individual,  e.g.  a  deer  with  large  horns  may  develop 
the  muscles  necessary  to  wield  them  successfully.  In 
order  that  such  muscular  development  may  become  estab- 
lished as  a  characteristic  of  the  species  there  must  be 
either  a  chance  or  mutating  variation  in  favor  of  greater 
muscular  development  or  else  the  presence  of  the  large 
horns  and  muscles  in  the  individual  must  so  affect  its 
reproductive  cells  that  the  tendency  to  the  growth  of  more 
muscular  tissue,  especially  in  the  neck,  is  produced  in  his 
descendants. 

THE    CELL    IN   INDIVIDUAL    AND    RACIAL    DEVELOPMENT 

All  organisms  are  composed  of  cells.  Recent  studies 
have  shown  that  most  cells  have  a  life  history  with  stages 
of  youth,  maturity,  and  old  age.  In  general,  young  cells 
have  a  large  nucleus,  while  old  cells  have  a  smaller  nucleus 
surrounded  by  a  larger  mass  of  protoplasm.  In  the  course 
of  development  the  nucleus  changes  little  except  in  size, 
while  the  protoplasm  differentiates  to  a  very  great  extent 
and  in  a  great  variety  of  ways  for  different  cells. 

In  young  cells,  i.e.  those  lately  developed  from  the  germ 
cell,  there  is  a  great  capacity  for  dividing  and  producing 
new  cells,  while  in  mature  cells  this  capacity  is  in  most 
cases  entirely  absent.  In  the  embryological  period  of 
individual  development  nearly  all  the  cells  are  engaged 


340  GENETIC   PSYCHOLOGY 

in  a  rapid  production  of  new  cells  like  themselves.  As 
development  proceeds  the  cells  already  produced  change 
in  character  and,  in  proportion  as  any  cell  differentiates, 
does  it  become  incapable  of  producing  new  cells.  In 
human  beings  at  birth  the  production  of  new  cells,  under 
ordinary  conditions,  has  nearly  ceased.  The  changes 
that  take  place  in  the  course  of  development  after  birth 
are  therefore  largely  due  to  specialization  and  to  increase 
in  size  of  cells  already  formed. 

The  capacity  for  producing  new  cells  under  special 
conditions  still  remains,  however,  in  some  portions  of  the 
body.  This  is  especially  true  of  the  surface  cells  of  the 
skin,  which  are  especially  liable  to  destruction.  A  consid- 
erable amount  of  connective  tissue  that  has  been  destroyed 
may  be  replaced,  which  would  not  be  possible  if  the  cells 
had  entirely  lost  their  capacity  to  produce  new  cells.  In 
the  case  of  muscular  cells  there  is  also  some  capacity  for 
producing  new  cells  and  thus  repairing  injuries.  A  slight 
degree  of  this  capacity  is  also  retained  by  the  cells  compos- 
ing special  organs,  such  as  the  liver.  In  the  nerve  cells, 
however,  which  are  capable  of  such  a  high  degree  of  special- 
ization, the  capacity  to  produce  new  cells  seems  to  be 
nearly,  if  not  entirely,  absent  at  birth,  though  parts  of  cells 
may  be  replaced,  e.g.  if  a  cell  body  is  destroyed,  its  fiber 
dies  and  is  not  renewed ;  but  if  the  fiber  only  is  cut  or 
destroyed,  a  new  one  may  grow  out  from  the  cell  body. 

This  power  of  producing  new  cells  to  take  the  place 
of  cells  or  parts  of  cells  that  have  been  destroyed  is  known 
as  regeneration.  It  is  very  much  greater  in  children  and 
young  animals,  which  are  composed  of  young  cells,  than  in 
those  that  have  reached  the  adult  stage ;  while  in  old  age  it 


R-^CIAL   AND    INDIVIDUAL    DEVELOPMENT         341 

IS  sometimes  almost  entirely  lost.  This  is  paralleled  in 
the  development  of  the  race  by  the  fact  that  in  the  lower 
animals  the  capacity  for  regenerating  parts  that  have  been 
lost  is  very  much  greater  than  in  the  higher  animals. 
Several  segments  may  be  removed  from  an  angleworm, 
and  the  lost  parts,  including  the  head,  will  be  regenerated. 
In  animals  still  lower  in  the  scale,  such  as  the  jellyfish 
and  the  stentor,  division  into  several  parts  is  followed  by 
regeneration  that  makes  a  complete  individual  of  each 
portion.  Even  in  animals  as  high  in  the  scale  as  crabs 
and  some  of  the  lower  vertebrates  the  removal  of  a  leg 
is  followed  by  its  complete  regeneration. 

An  examination  of  the  cells  composing  the  bodies  of 
lower  and  higher  animals  shows  that  in  general  the  cells 
constituting  the  bodies  of  the  lower  animals  are  less  com- 
pletely developed  and  highly  specialized  than  those  com- 
posing higher  animals.  Speaking  in  a  very  general  way 
we  therefore  say  that  the  characteristics  of  cells  in  lower 
animals  are  similar  to  those  of  the  cells  of  the  young  of 
higher  animals. 

In  general,  a  cell  that  has  been  matured  and  specialized 
is  not  capable  of  producing  new  cells.  In  lower  animals 
that  produce  by  fission,  it  has  been  found  that  after  a 
certain  number  of  generations  have  been  produced  the 
capacity  to  produce  decreases,  unless  there  is  a  conjuga- 
tion of  cells,  which  is  usually  followed  by  increased  capac- 
ity to  produce  new  cells.  In  the  case  of  higher  animals, 
where  there  is  sexual  rei)roduction,  the  cells  for  that  pur- 
pose are  usually  set  a])art  before  much  ditTerentiation  has 
taken  place  in  the  embryo,  and  the  reproductive  cells  re- 
main unspecialized.     After  two  such  cells  from  difTerent 


342  GENETIC   PSYCHOLOGY 

individuals  have  united,  changes  take  place  rapidly ;  the 
nucleus  of  the  germ  cell  thus  formed  divides  again  and 
again  as  it  develops  into  an  individual  of  the  species. 

RELATIONS  OF  CELLS  IN  DEVELOPMENT 

In  the  case  of  lower  animals  death  results  only  from  the 
destruction  or  loss  of  vitality  of  all,  or  a  considerable  portion, 
of  the  cells  of  which  they  are  composed.  As  we  have 
already  seen,  if  only  a  part  of  the  cells  of  a  lower  animal 
are  destroyed,  the  other  cells  produce  new  ones  to  replace 
the  parts  that  have  been  removed.  In  the  case  of  man 
and  the  higher  animals,  however,  death  rarely  results  from 
the  destruction  or  the  old  age  of  a  large  portion  of  the  in- 
dividual cells  composing  the  body.  Most  of  the  cells  are 
still  vigorous  and  without  signs  of  degenerative  changes. 
Conversely  it  is  possible  to  remove  from  the  body  a  mus- 
cle or  even  the  heart  and  by  means  of  artificial  circulation 
keep  it  actively  functioning  long  after  the  animal  as  a 
whole  is  dead.  Death  in  higher  animals  usually  results 
from  the  injury  or  loss  of  functioning  power  of  the  cells 
composing  some  particular  organ  of  the  body,  without 
whose  activity  the  rest  of  the  organs  are  unable  to  function 
properly.  The  difference  between  a  lower  animal  and  a 
higher  one  consists,  not  merely  in  the  character  of  the 
cells  composing  the  body,  but  chiefly  in  the  relation  of 
the  various  specialized  cells  to  each  other,  and  the  same 
is  true  of  the  differences  between  an  animal  at  birth  and 
when  mature. 

In  single  celled  animals,  life  is  maintained  by  harmoniza- 
tion of  the  activities  of  the  cell  with  the  environment  im- 


RACIAL  AND   INDIVIDUAL   DEVELOPMENT        343 

mediately  affecting  it.  In  animals  composed  of  more  than 
one  cell  all  the  other  cells  constitute,  in  effect,  an  important 
stimulating  environment  for  each  individual  cell.  To 
maintain  life  the  activity  of  each  cell  must  be  harmonized 
not  only  with  its  immediate  external  environment,  but  also 
with  the  activities  of  the  other  cells.  So  long  as  the  many 
cells  of  which  the  organism  is  composed  are  similar  and 
undifferentiated,  their  influence  is  less  significant.  This  is 
shown  by  the  fact  that  the  removal  of  large  numbers  of 
cells  from  lower  animals  makes  little  difference  in  their 
activity,  except  that  opportunity  is  then  given  for  exercising 
more  fully  the  capacity  to  produce  new  cells.  This  soon 
results  in  regeneration  or  replacement  of  the  cells  which 
have  been  removed.  Even  in  these  lower  organisms, 
however,  the  relation  of  part  to  part  is  of  a  good  deal  of 
significance.  If  too  many  cells  are  removed  for  the  re- 
generating power  of  an  animal  of  a  given  degree  of  organi- 
zation, regeneration  does  not  take  place. 

The  decreased  power  of  regeneration  in  higher  animals  is 
probably  due  in  part  to  the  variety  of  cells  in  the  different 
structures  of  the  body  and  to  a  lack  of  correspondence  in  the 
rate  of  development  of  the  various  new  cells  when  any 
portion  of  the  body  has  been  removed.  The  reason  why  a 
lost  limb  is  replaced  in  a  newt  and  not  in  man  is  probably 
because  the  highly  differentiated  cells  composing  the  bones, 
muscles,  blood  vessels,  nerves,  and  skin  of  man,  cannot 
produce  new  cells  at  the  rate  necessary  for  the  harmonious 
functioning  of  cells  of  one  kind  in  relation  to  cells  of  the 
other  kinds. 

As  we  have  already  seen,  the  less  specialized  cells 
composing  the  connective  tissue  have  much  greater  capacity 


344  GENETIC   PSYCHOLOGY 

for  producing  new  cells  than  have  the  highly  specialized 
nerve  cells.  We  may  note  also  that  the  possibility  of 
specialization  as  the  result  of  exercise  and  growth  is  very 
much  less  in  the  connective  tissue  cells  than  in  the  nerve 
cells.  In  other  words,  the  cells  that  have  the  least  capacity 
to  produce  new  cells  have  the  greatest  capacity  for  change 
and  specialization,  and  the  reverse. 

On  the  other  hand,  every  organism  has,  within  certain 
limits,  a  normal  size  at  maturity.  It  has  some  capacity  to 
produce  new  cells,  as  is  shown  in  the  phenomenon  of  regen- 
eration ;  but  new  cells  that  might  increase  the  size  of  the 
animal  are  not  produced  as  long  as  the  animal  is  uninjured, 
evidently  because  the  tendency  is  checked  by  the  relation  of 
one  part  of  the  animal  to  other  parts.  Not  only  growth  but 
development  and  specialization  of  structure  in  different 
parts  of  the  body  are  therefore  probably  due  to  the  relation 
of  cells  and  organs  to  each  other  rather  than  to  the  mere 
character  of  the  individual  cells. 

It  follows  also  from  this  that  the  changes  that  take  place 
in  the  development  of  animals  from  lower  to  higher  types 
of  organization,  and  in  the  development  of  individuals  from 
the  embryo  to  infancy  and  from  infancy  to  maturity,  are 
influenced  to  a  greater  and  greater  extent  by  the  relation 
of  cells  to  each  other,  and  less  and  less  by  the  direct  in- 
fluence of  the  external  environment  upon  the  development 
of  individual  cells.  The  greater  the  variety  and  degree  of 
specialization  in  the  cells  of  an  organism  the  more  will  the 
activity  and  development  of  each  part  be  influenced  by 
every  other  part.  It  is  a  well-known  fact  in  physiology 
that  the  removal  of  a  single  apparently  insignificant  organ, 
such  as  the  thyroid  gland,  produces  profound  changes  in 


RACIAL  AND   INDIVIDUAL  DEVELOPMENT         345 

the  whole  process  of  develo[)mcnt.  The  functioning  and 
growth  of  every  organ  of  the  body  is  thus  modified  and  the 
individual  is  weak  and  undeveloped  both  physically  and 
mentally.  One  form  of  idiocy  is  due  to  deficiency  in  this 
gland,  and  extract  of  the  thyroid  of  sheep  often  produces 
great  improvement.  In  man  the  removal  of  the  primary 
organs  of  sex  at  an  early  age  causes  profound  modifica- 
tions in  the  physical  and  mental  development,  the  second- 
ary physiological  characteristics,  such  as  beard,  change  of 
voice,  etc.,  failing  to  appear  in  the  male  and  becoming 
prominent  in  the  female. 

It  is  known  that  the  production  of  new  individuals  in 
lower  organisms  is  limited  by  the  fact  that  a  substance  un- 
favorable to  further  reproduction  is  produced.  It  has 
been  suggested  by  Tayler  and  others  that  in  their  growth 
all  the  cells  of  the  human  body  produce  substances  that  may 
retard  or  accelerate  the  growth  of  other  cells  of  the  body. 
If  this  is  true,  the  thyroid  gland  is  simply  an  extreme  ex- 
ample of  what  is  true  in  a  less  degree  of  every  organ.  The 
importance  of  the  relation  of  cells  to  each  other  and  the 
consequences  of  environing  influences  are  emphasized  by 
the  following  facts.  Tumors  may  be  transplanted  from 
one  mouse  to  another  and  made  to  grow,  but  the  rate  and 
extent  of  growth  vary  not  only  with  the  variety  of  the 
mouse  used,  but  also  in  the  same  variety,  if  the  mice  have 
been  subjected  to  different  food  and  climatic  conditions. 
It  may  be  that  all  abnormal  growths,  such  as  tumors  and 
cancers,  arc  due  to  disturbance  of  normal  relations  in  the 
growth  processes  by  means  of  which  retarding  substances 
are  not  supplied  to  certain  cells,  or  unusual  accelerating 
influences  are  given  them.  When  the  whole  organism  is 
thus  affected  the  result  may  be  a  dwarf  or  a  giant. 


346  GENETIC   PSYCHOLOGY 

The  disturbance  of  the  function  of  one  part  during  the 
growing  period  may  produce  disturbance  of  function  of 
many  other  parts  and  thus  cause  profound  changes  in  the 
development  of  all  organs  concerned.  For  example,  the 
abnormal  growth  of  adenoids  interfering  with  the  passage  of 
air  through  the  nose  leads  to  mouth  breathing  and  to  less 
aeration.  The  secondary  changes  that  may  follow  are  a 
V-shaped  palate,  chisel-shaped  teeth,  a  considerable  modifi- 
cation of  the  external  nose,  especially  at  the  openings  and 
near  the  eyes,  imperfect  development  of  the  lungs  and  of  the 
muscular  and  bony  wall  inclosing  them  (a  condition  known 
as  "pigeon  breast"),  changes  in  the  middle  ear,  leading  to 
partial  deafness,  and  finally  a  marked  retardation  in  the 
brain  development. 

We  may  note  again  that  in  a  creature  composed  of  a 
variety  of  specialized  cells  where  relation  of  part  to  part  is  of 
such  significance  in  development,  we  always  find  a  large 
number  of  nerve  cells  which  serve  the  purpose  of  con- 
necting each  kind  of  cell  with  every  other  kind.  In  this 
way  the  functioning  of  cells  in  one  part  of  the  body  may 
readily  be  affected  by  and  harmonized  with  the  functioning 
of  cells  in  other  parts  of  the  body.  Besides  this  primary 
functioning  of  the  nerve  cells  there  is  also  a  secondary 
function  that  in  higher  animals  is  of  equal  importance. 
In  them,  nerve  cells  not  only  connect  all  parts  of  the  body 
with  each  other  so  that  each  is  influenced  by  all  the  others, 
but  the  activity  of  the  nerve  cells  becomes  the  most  im- 
portant influence  affecting  the  activity  of  other  cells.  This 
is  perhaps  a  natural  result  of  the  high  degree  of  modifiability 
possessed  by  the  nerve  cells.  They  are  so  readily  changed  in 
their  functioning  and  structure  by  what  they  do,  and  retain 


RACIAL   AND    INDIVIDUAL   DEVELOPMENT         347 

SO  perfectly  the  effects  of  previous  experience,  that  they 
influence  the  action  of  other  portions  of  the  body  not  only 
because  of  the  activity  excited  in  them  by  present  stimulation, 
but  also  by  the  stored  up  results  of  past  stimulations.  It 
is  well  recognized  in  physiology  that  the  nerv^ous  system 
exercises  a  very  important  trophic  influence  upon  all  parts 
of  the  body,  since  any  lack  of  nervous  supply  or  imperfect 
nervous  functioning  modiflcs,  in  a  marked  degree,  growth 
processes. 

It  is  evident  that  the  relation  of  the  nerve  cells  to  the 
muscle  cells  is  especially  close  and  that  the  development  of 
the  muscles  is  almost  completely  dominated  by  the  activity 
of  the  nerve  cells,  at  least  after  birth.  Even  more  marked 
is  the  effect  of  the  activity  of  each  portion  of  the  nervous 
system  upon  the  activity  of  every  other  portion  of  that 
system.  In  general,  in  the  early  stages  of  life  in  human 
beings,  the  nerve  cells  in  the  spinal  cord  and  lower  portions 
of  the  brain  excite  to  activity  the  higher  centers  in  the  cortex. 
In  later  life  the  influence  is  more  in  the  other  direction,  the 
higher  conceptual  and  representative  centers  modifying  the 
activity  of  the  sensory  motor  centers.  It  is  evident  that  in 
the  case  of  the  nervous  system  the  characteristics  of  individ- 
ual cells  are  of  very  slight  importance  compared  with  the 
relation  of  groups  of  cells  in  the  nervous  system  to  each 
other  and  to  other  portions  of  the  body.  We  may  say, 
therefore,  that  not  only  in  higher  species,  but  also  in  individ- 
uals, as  cells  become  more  specialized  so  does  the  rela- 
tion of  part  to  part  become  of  increasing  importance. 

Not  only  does  relation  of  part  to  part  become  more 
and  more  important  with  increased  specialization  of  parts, 
but,  as  we  have  already  shown,  the  most  efl'ective  form  of 


348  GENETIC   PSYCHOLOGY 

nervous  and  motor  organization  is  that  in  which  compara- 
tively few  parts  may  be  made  to  act  in  various  relations 
with  other  parts,  as  is  the  case  with  the  two  hands  of  man. 
Furthermore,  the  higher  animals  survive  not  only  because 
the  parts  of  their  own  bodies  are  properly  related  to  each 
other,  but  because  of  the  relation  in  structure  and  instincts 
between  offspring  and  parents,  and  also  because  of  the 
relation  of  individuals  to  others  of  their  kind.  In  man  this 
relationship  to  others  extends  beyond  the  immediate  envi- 
ronment, so  that  physical  and  especially  mental  develop- 
ment depends  in  part  upon  the  influence  exerted  by  other 
people  far  distant  in  time  and  space.  The  forms  of  the 
athletes  of  to-day  are  determined  in  part  by  ideas  associated 
with  the  activity  of  nerve  cells  in  the  brains  of  the  Greeks. 

SELECTION  IN  INDIVIDUAL  AND  RACIAL  EVOLUTION 

There  are  great  differences  of  opinion  among  scientists 
as  to  the  causes  of  variation  in  individuals  of  the  same  and 
successive  generations  of  the  same  species,  but  there  is 
universal  agreement  that  natural  selection  is  the  chief 
factor  in  determining  what  individuals  of  the  species  with 
their  special  modes  of  behavior  and  structure  shall  sur- 
vive. It  is  now  also  recognized  that  of  the  various  trial 
movements  made  by  an  individual,  those  are  selected  for 
survival  which  have  favorable  results  and  that  the  organs 
concerned  in  the  production  of  those  movements  are  thus 
developed.  There  are,  however,  important  differences  in 
the  selection  of  behavior  and  structure  for  survival  in  the 
species  and  in  the  individual. 

In  racial  development  modes  of  behavior  and  structure 


RACIAL   AND   INDIVIDUAL   DEVELOPMENT         349 

are  selected  for  survival  by  the  preservation  of  the  lives  of 
individuals  having  those  characteristics  long  enough  for 
them  to  produce  descendants  similar  to  themselves.  The 
selection  is  made  in  a  negative  rather  than  a  positive  way. 
All  individuals  that  at  any  stage  of  their  development  have 
characteristics  of  cells  or  of  relations  of  cells  to  each  other 
that  are  sufficiently  unfavorable  to  survival  are  eliminated, 
and  those  characteristics  never  again  have  a  chance  to 
develop  in  the  species,  unless  it  be  by  some  variation 
similar  to  that  which  gave  rise  to  them  before. 

Again,  it  is  generally  true  that  the  individual  is  engaged  in 
a  struggle  for  existence  not  only  against  unfavorable  condi- 
tions in  the  physical  environment,  but  also  against  other 
individuals  of  his  own  and  of  other  species.  There  are  some 
exceptions  to  this  among  the  lower  animals  and  an  increas- 
ing number  among  the  higher.  In  most  of  the  lower 
vertebrates,  as  for  example  fishes,  there  is  no  cooperation 
between  individuals ;  parents  are  even  likely  to  destroy  their 
own  young.  Survival  in  such  creatures  depends  chiefly 
upon  the  enormous  number  of  individuals  produced. 
Among  higher  vertebrates  the  parents  assist  for  a  longer  or 
shorter  time  the  individuals  of  the  next  generation  instead 
of  engaging  in  a  struggle  for  existence  against  them.  In 
all  such  cases  the  survival  of  the  species  depends  upon  the 
correlation  between  the  instincts  of  the  young  and  the  in- 
stincts of  the  parent.  Any  failure  of  the  instincts  of  the 
young  to  match  those  of  the  parent  may  result  in  death. 
In  social  animals  we  have  a  farther  development  of  coopera- 
tion, adults  of  the  same  species  cooperating  in  their  activi- 
ties in  securing  food  and  in  repelling  and  escaping  enemies. 
Even  in  these  cases,  however,  there  is  a  large  amount  of 


350  GENETIC   PSYCHOLOGY 

conflict  between  individuals  of  the  same  species,  and  the 
results  of  these  conflicts  determine  to  a  considerable  extent 
what  ones  shall  obtain  food  and  produce  descendants;  and 
hence  evolutionary  progress  in  the  species  is  determined 
more  by  competition  than  by  cooperation. 

In  some  cases,  especially  among  insects,  there  is  a  sort  of 
cooperation  between  different  species  and  different  varieties 
of  the  same  species  in  a  way  known  as  symbiosis.  The 
relation  of  ants  and  aphids,  their  so-called  "cows,"  and  of 
slave-making  ants  and  their  "slaves"  are  examples  of 
different  species  and  varieties  cooperating  with  mutual 
advantage.  The  same  may  be  said  of  some  forms  of 
parasitism,  though  usually  in  such  cases  the  parasite  species 
profits  by  the  relation  without  giving  any  corresponding 
advantage  to  the  host  species.  In  the  relation  between 
insects  and  plants  we  have  a  remarkable  example  of 
mutually  helpful  structure  and  mode  of  behavior  by  which 
the  insects  obtain  food  and  the  plants  are  properly  fertilized. 
Notwithstanding  these  interesting  exceptions  it  is  the  general 
rule  that  the  individuals  of  every  species  are  in  conflict, 
not  only  with  other  species,  but  also  to  a  considerable 
extent  with  other  individuals  of  their  own  species,  and  all 
evolution,  so  far  as  it  depends  upon  natural  selection,  is  the 
result  of  eliminating  individuals  and  with  them  the  modes 
of  behavior  and  structure  least  favorable  to  survival. 
With  progress  to  higher  forms,  reactions  to  other  living 
creatures  become  more  and  more  important  as  compared 
with  reactions  to  the  physical  environment. 

The  struggle  for  existence  is  less  severe  between  parts 
of  the  individual  than  between  individuals  in  the  species. 
There  may  be  something  of  a  struggle  between  the  different 


RACIAL   AND    INDIVIDUAL   DEVELOPMENT         351 

cells,  but  this  cannot  be  a  prominent  feature  of  individual 
development,  otherwise  the  harmony  of  parts  which  is 
absolutely  necessary  for  the  maintenance  of  life  would  not 
be  possible.  If  there  is  a  struggle  between  the  different 
cells,  it  is  a  struggle  for  position  or  prominence  in  the  or- 
ganism instead  of  a  struggle  that  means  survival  for  some 
cells  and  death  for  others.  The  same  is  true  of  the  social 
struggles  of  man.  In  general,  the  relation  between  the 
different  cells  of  the  body  must  be  that  of  mutual  influence 
of  each  upon  all  the  others,  and  cooperation  must  be  the  rule 
rather  than  the  exception. 

In  the  development  of  an  individual  from  the  original 
germ  cell  to  maturity,  selection  is  all  the  time  acting  in  such 
a  way  as  to  make  certain  activities  prominent  and  thus 
develop  certain  types  of  structure  and  relation  of  part  to 
part.  In  this  case,  however,  selection  is  not  simply  a  nega- 
tive factor  in  evolution.  It  is  true  that  useless  movements, 
and  especially  those  that  are  harmful,  are  not  repeated  to 
any  great  extent.  The  useful  movements  are  repeated, 
however,  not  merely  because  they  are  not  eliminated,  but 
because  of  their  favorable  results.  They  are  not  only 
repeated  because  of  native  tendencies  to  that  form  of 
movement,  but  the  tendency  to  make  such  movements  in- 
creases positively  and  in  a  very  marked  degree  because  of 
their  repetition. 

Again,  modes  of  behavior  which  do  not  prove  suitable  in 
a  given  environment  or  at  a  given  stage  in  the  development 
of  an  individual,  are  not  always  permanently  eliminated  by 
failure  at  that  time,  as  is  the  individual  in  racial  develop- 
ment. Modes  of  behavior  that  at  one  time  are  useless  or 
harmful  may  appear  again  and  prove  useful  under  other 


352  GENETIC   PSYCHOLOGY 

circumstances  or  at  another  stage  of  development,  and  then 
become  permanent  characteristics  of  the  individual. 

It  is  evident,  therefore,  that  selection  operates  in  a  much 
less  decisive  and  irrevocable  way  in  the  evolution  of  the 
individual  than  in  the  development  of  the  race.  Many 
varieties  of  behavior  may  therefore  appear  and  persist  in  the 
individual  for  long  periods  of  time  that  never  become  in- 
herited characteristics  of  the  species. 

Wherever  individuals  are  able  to  modify  their  behavior 
in  any  way  it  must  be  that  they  inherit  the  capacity  for 
such  modification.  This  capacity  for  modification  in  vari- 
ous ways  may  be  increased  indefinitely  in  the  species,  while 
the  actual. modifications  can  take  place  only  in  the  indi- 
vidual. This  is  the  feature  of  development  that  becomes 
more  and  more  prominent  as  we  go  upward  in  the  scale 
of  animal  life  and  becomes  almost  the  exclusive  feature 
in  human  development.  Very  few  definite  and  specific 
modes  of  behavior  other  than  those  common  to  animals 
have  become  established  in  the  human  race,  while  the  ca- 
pacity to  develop  to  almost  any  degree  in  an  infinite  variety 
of  ways  is  so  great  that  in  this  respect,  more  than  any 
other,  man  is  distinguished  from  all  other  animals. 

There  is  good  reason  to  believe  that  the  change  in  evolu- 
tion, from  the  development  of  specific  structures  and  modes 
of  behavior  in  the  species  to  the  development  of  capacity 
in  the  individuals  of  a  species  to  acquire  modes  of  behavior, 
is  very  closely  correlated  with  the  development  of  conscious- 
ness, which  we  have  already  found  is  so  likely  to  be  present 
when  behavior  is  changing,  and  which  is  largely  absent 
in  fixed  reflex  and  instinctive  behavior.  Selection,  which 
works  in  a  negative  way  by  destroying  individuals  with 


RACIAL   AND   INDIVIDUAL   DEVELOPMENT         353 

modes  of  behavior  unsuited  to  survival,  is  made  effective  in 
the  development  of  the  individual  by  the  pain  that  accom- 
panies such  behavior  in  a  creature  that  is  conscious.  If, 
when  pain  is  felt,  the  action  ceases  or  is  modified  before 
serious  injury  has  resulted,  the  individual  may  survive. 
Pain  thus  serves  as  a  substitute  for  death.  It  is  a  more 
economical  means  of  evolution  in  the  species  than  death 
and  favors  variety  of  action  in  the  individual. 

This  negative  action  of  consciousness  is  supplemented  by 
the  positive  influence  of  pleasure.  All  the  modifications 
in  behavior  produced  by  pain,  which  bring  relief  and 
pleasure,  are  likely  to  be  repeated  and  thus  developed. 
The  variety  of  behavior  and  the  rapidity  and  extent  of 
development  is  thus  greatly  increased  by  consciousness. 
A  further  development  of  consciousness  that  makes  reac- 
tion to  suggestive  stimuli  more  nearly  perfect,  enables  the 
individual  to  modify  its  behavior  before  injury  is  actually 
experienced. 

With  a  further  development  of  consciousness  giving 
foresight  as  to  means  of  avoiding  painful  and  securing 
pleasurable  stimuli  in  the  future,  the  possibilities  of  varied 
development  in  the  individual  are  greatly  increased. 
We  may  expect  to  find  in  man,  therefore,  much  greater 
individual  differences  than  in  animals  and  to  find  that  there 
is  a  great  deal  in  his  individual  development  that  has  no 
parallel  in  the  de\'elopment  of  the  race. 

In  many  instances  also  we  may  expect  to  find  capacities 
and  powers  that  have  little  or  no  biological  value  because 
neither  harmful  nor  helpful  to  the  species.  So  long  as  men 
do  nothing  that  brings  disease  and  death  they  may  take  a 
thousand  different  means  of  avoiding  painful  experiences 
a  A 


354 


GENETIC   PSYCHOLOGY 


and  securing  pleasures  without  subjecting  themselves  to  the 
law  of  natural  selection. 

This  extraordinary  development  of  individuals  in  vari- 
ous directions  under  the  influence  of  conscious  pain  and 
pleasure  is  not,  however,  entirely  without  effect  upon  the 
evolution  of  the  race.  Men  find  many  of  their  pains  and 
pleasures  in  association  with  each  other,  and  individuals 
who  find  their  pleasures  in  ways  that  are  painful  to  others, 
if  not  actually  eliminated  by  their  fellow-men,  may  not 
receive  as  much  help  from  others  and  may  not  have 
as  good  an  opportunity  to  produce  descendants.  Again, 
individuals  who  find  their  pleasures  in  the  same  way  are 
more  likely  to  cooperate  and  to  marry.  The  descendants 
of  parents  with  great  capacity  for  one  kind  of  enjoyment, 
e.g.  aesthetic  pleasures,  are  likely  to  have  more  capacity 
for  such  pleasures  than  their  parents.  In  this  way  we 
may  account  for  the  development  of  many  psychical 
characteristics  that  have  no  biological  value.  It  is  evi- 
dent, therefore,  that  consciousness  must  have  been 
one  of  the  chief  factors  in  the  development  of  the  human 
race  beyond  the  stage  reached  by  other  animals. 

ENLARGEMENT      OF      ENVIRONMENT      IN      THE     EVOLUTION 
OF    THE    RACE    AND    THE    INDIVIDUAL 

The  importance  of  environment  in  evolution  does  not 
depend  upon  the  theory  that  variations  are  produced  by 
environment.  Natural  selection  is  determined  by  the  en-- 
vironment,  and  any  change  in  environment  is  likely  to 
eliminate  certain  modes  of  behavior  and  certain  structural 
characteristics  not  affected  by  the  previous  environment^ 


RACIAL   AND    INDIVIDUAL   DEVELOPMENT         355 

and  thus  make  others  relatively  more  prominent.  The 
characteristics  that  are  selected  for  survival  in  the  evolu- 
tion of  the  race  and  the  individual  are  therefore  determined 
by  the  environment  in  which  the  organism  develops. 

In  a  general  way  environment  is  usually  understood  to 
refer  to  the  immediate  external  surroundings  of  the  or- 
ganism. In  truth,  however,  environment,  as  a  factor  in 
evolution,  should  refer  chiefly  to  the  surroundings  that  in 
any  way  affect  the  activity  of  the  organism  and  thus  deter- 
mine its  development.  In  this  sense  creatures  living  in 
immediate  proximity  do  not  necessarily  have  the  same 
environment.  One  may  be  profoundly  affected  by  some- 
thing in  the  surroundings  that  exercises  no  perceptible 
influence  upon  another.  The  conversation,  books,  and 
pictures  in  the  home  are  immensely  important  phases  of 
the  environment  of  the  child,  but  they  play  no  part  worth 
noticing  in  the  development  of  the  kitten  having  the  same 
material  surroundings. 

Young  animals  have  quite  a  different  environment  from 
the  same  animals  when  matured.  They  are  limited  in  their 
movements,  protected  from  climatic  influences  and  enemies, 
and  supplied  with  food  by  their  parents.  .\s  they  develop, 
go  into  new  surroundings,  and  begin  to  secure  their  own 
food,  they  meet  with  entirely  different  kinds  of  environ- 
ment to  which  they  must  react  appropriately.  Even  in 
the  case  of  mature  animals  it  cannot  be  said  that  the  en- 
vironment to  which  they  are  reacting  remains  the  same 
even  in  the  same  locality.  A  bird,  for  example,  that  is 
building  a  nest,  is  affected  by  nest-building  materials  that, 
under  other  circumstances,  would  probably  exercise  no 
influence  upon  her  behavior.     In  general,  it  may  be  said 


356  GENETIC   PSYCHOLOGY 

that  as  a  creature  matures  it  reacts  to  more  phases  of 
any  environment  in  which  it  is  at  the  moment,  and  being 
able  to  move  more  freely  it  thus  meets  with  more  varia- 
tions in  surroundings. 

In  racial  development  it  is  evident  that  the  simpler  or- 
ganisms are  affected  by  few  elements  of  the  environment, 
and  the  higher  by  many.  The  lower  organisms  react 
chiefly  to  physical  and  chemical  stimuli,  while  the  higher 
organisms,  with  many  special  sense  organs,  react  to  a  great 
variety  of  objects  and  characteristics  that  have  little  or  no 
physical  or  chemical  effect  upon  them.  Every  increase  in 
variety  of  sense  organs  results  in  an  increase  in  the  variety 
of  environment  affecting  the  organism.  Every  increase 
in  sensitivity  and  in  the  possibility  of  varied  movement  in- 
creases the  number  of  characteristics  of  the  environment 
that  may  affect  the  organism.  The  needs  of  a  creature 
and  its  instinctive  tendencies,  which  are  largely  determined 
by  its  structure,  mark  out  for  it  the  portion  of  the  environ- 
ment that  shall  influence  it  most.  In  both  the  individual 
and  the  race,  positive  psychical  needs  become  more  and 
more  important  as  higher  stages  of  development  are 
reached. 

From  the  above  it  is  clear  that  an  individual  must  diverge 
more  and  more  in  its  development  from  that  of  the  race  as  it 
passes  from  the  embryological  and  infantile  stages  into 
more  mature  stages  of  development,  and  that  this  diver- 
gence must  be  greater  in  proportion  as  capacities  for  modi- 
fication increase  and  as  the  individual  becomes  subject 
to  the  influences  of  a  wider  and  wider  environment.  Much 
has  been  said  about  the  correspondence  between  the  intel- 
lectual development  of  the  child  and  of  the  race,  but  this  is 


RACIAL   AND    INDIVIDUAL    DEVELOPMENT         357 

just  where  there  must  be  least  correspondence  so  far  as 
the  apparatus  involved  in  the  higher  intellectual  process  is 
concerned.  Since,  in  the  nervous  system,  capacity  for 
modification  is  greater  than  in  any  other  part  of  the  body, 
and  since,  as  we  shall  see,  the  environment  affecting  the 
development  of  the  child  is  entirely  different  from  that 
affecting  the  race,  it  follows  that  there  is  little  chance  for 
the  higher  nerve  centers  to  be  modified  in  the  child  in  the 
same  way  as  they  have  been  in  the  race. 

The  child  and  the  savage  resemble  each  other  chiefly 
because  they  are  both  to  a  considerable  extent  undeveloped 
intellectually.  Both  have  the  physiological  and  instinctive 
characteristics  of  the  race,  but  they  are  in  different  stages, 
some  instincts  being  more  prominent  in  one  and  some  in 
the  other,  e.g.  imitative  instincts  in  the  child  and  sexual 
in  the  savage.  They  are  like  each  other  in  that  the  higher 
nervous  structures  are  only  partially  developed  and  hence 
exercise  much  less  influence  over  the  rest  of  the  organism. 
The  sensory  motor  apparatus  is  well  developed  in  both  the 
child  and  the  savage,  and  therefore  their  behavior  is  in 
some  respects  similar. 

In  the  development  of  the  child  and  the  race  the  order 
in  which  the  different  kinds  of  intelligence  appear  is  doubt- 
less the  same,  physiological  intelligence  appearing  first, 
successively  followed  by  sensory  motor,  representative,  and 
conceptual  intelligence.  Since  representative  and  con- 
ceptual intelligence  are  developed  almost  wholly  by  ex- 
perience, there  can  be  a  close  parallel  in  the  development 
of  the  higher  forms  of  intelligence  in  the  race  and  the  child 
only  when  both  have  been  subjected  to  similar  and  ever- 
broadening  environments.     This  has  been  true  to  some 


358  GENETIC   PSYCHOLOGY 

extent,  but  few  phases  of  the  broader  environment  have 
acted  long  enough  on  the  race  or  in  the  same  way  upon 
individuals  of  the  species  to  produce  an  appreciable  influ- 
ence upon  the  nervous  structure  of  the  species,  though  in 
the  individual  a  complete  transformation  may  be  produced 
in  a  very  short  time. 

PHYSIOLOGICAL    EVOLUTION   IN  MAN 

Man,  in  his  physiological  development,  is  probably 
influenced  less  by  physical  surroundings  than  any  other 
species  of  animal.  He  is  able  to  maintain  life  in  every 
zone,  and  in  his  chief  physiological  features  he  is  the  same 
wherever  found.  This  is  due,  in  part,  to  his  intelligence, 
which  enables  him  to  protect  himself  from  his  immediate 
environment  and  prepare  for  future  needs.  Races  of  men 
differ  somewhat  in  size  and  proportion  of  parts,  but  espe- 
cially in  color  of  hair,  eyes,  and  skin,  where  they  have  not 
migrated  and  intermarried.  These  differences  are  doubt- 
less due  to  the  selective  influence  of  climate  and  modes  of 
life  lasting  long  enough  to  produce  distinct  effects. 

Aside  from  differences  in  climate,  the  most  important 
changes  in  environment  affecting  the  evolution  of  man 
are  to  be  expected  in  the  conditions  of  city  life,  where  the 
environment  has  been  entirely  transformed  by  man  and 
where  men  are  engaged  in  a  great  variety  of  specialized 
activities  unknown  to  the  savage.  This  change  to  city 
life,  which  is  such  a  marked  feature  in  modern  civilization, 
is  like  transporting  the  human  race  into  a  new  world  where 
it  is  subjected  to  many  new  environing  influences.  In  the 
city,  with  its  mechanical  modes  of  controlling  temperature, 


RACIAL   AND    INDIVIDUAL   DEVELOPMENT         359 

light,  and  means  of  obtaining  food,  latitude  makes  little 
difference.  The  practice,  however,  of  having  the  skin 
subjected  to  little  variation  in  temjoeraturc,  and  i)rotccted 
from  air  and  sunlight,  of  breathing  air  deficient  in  oxygen, 
and  filled  with  gases  and  germs  of  various  kinds,  and  of 
feeding  upon  prcj^ared  foods,  while  engaging  in  highly 
specialized  activities  involving  little  muscular  effort,  must 
in  time  exercise  an  important  selective  influence  upon  the 
human  race.  While  it  is,  under  these  conditions,  less 
subject  to  some  forms  of  disease  than  under  the  more 
primitive  conditions  of  life,  it  is  more  subject  to  other 
forms  of  disease,  especially  those  due  to  germs  that  thrive 
under  such  conditions  of  life,  e.g.  tuberculosis.  One  of 
the  chief  factors  in  determining  the  type  of  phvsical  organi- 
zation that  shall  survive  under  modern  conditions  is  that 
of  ability  to  resist  the  attacks  of  various  germ  diseases. 

Another  important  factor  determining  the  physiological 
type  of  the  future  man  and  woman  is  the  character  of 
activity  required  in  order  to  succeed  in  the  conditions  of 
city  life.  Under  primitive  conditions  of  life,  vigor  of  skin, 
of  muscles,  and  digestive  apparatus  were  the  chief  factors 
in  survival,  while  under  modern  conditions  continual  and 
varied  activity  of  the  nervous  system  is  required.  In  cross- 
ing a  few  crowded  streets  there  are  a  greater  number  and 
variety  of  sensory  motor  adjustments  than  in  walking  a  mile 
in  the  country;  while  a  business  man  in  his  ofi'ice,  in  an 
hour's  time,  may  make  more  representative  and  conceptual 
adjustments  than  the  savage  makes  in  a  whole  year.  The 
general  result,  therefore,  is  that  those  who  cannot  endure 
this  continuous  and  varied  activit}-  of  the  nervous  system 
fail  in  the  struggle  for  existence.     Hence  the  tendency  is 


360  GENETIC   PSYCHOLOGY 

in  the  direction  of  selecting  for  survival  the  nervous  type 
of  human  beings  so  far  as  such  an  organization  is  consistent 
with  the  preservation  of  a  proper  balance  and  harmony  of 
relation  between  the  nervous  structure  and  other  portions 
of  the  body. 

This  tendency  is,  however,  counteracted  and  limited  in 
various  ways.  A  larger  central  nervous  system  means  a 
larger  head,  and  since  infants  with  large  heads  are  likely 
to  die  at  birth,  this  cannot  become  a  much  more  prominent 
characteristic  of  the  race.  In  modern  life,  also,  failure  to 
succeed  does  not,  in  most  cases,  mean  death,  as  it  does 
among  animals  and  to  a  considerable  extent  among  savage 
races.  The  individual  who  fails  continues  to  live,  and  in 
a  large  proportion  of  cases  produces  descendants.  The 
application  of  the  results  of  medical  research  in  such 
way  as  to  protect  men  from  elimination  by  disease  germs, 
and  the  limitation  of  the  hours  of  specialized  labor  and 
the  increase  in  athletic  and  recreative  activities  involving 
muscular  activity,  are  also  counteracting  influences. 

The  changes  affecting  the  physiological  development 
of  the  human  race  are  so  slow  that  the  effects  of  changed 
environment,  as  found  in  our  modern  cities,  have  as  yet 
produced  a  scarcely  discernible  influence.  In  the  case 
of  individuals,  however,  the  effects  of  environment  are  so 
rapid  and  profound  that  a  few  years'  residence  makes  a 
very  striking  change  in  the  physiological  processes  of  the 
individual.  Every  occupation  produces  some  modifica- 
tion of  the  physical  type,  while  living  in  a  special  environ- 
ment during  childhood,  and  engaging  at  an  early  age  in 
an  occupation  involving  specialized  activity,  produce  pro- 
found changes  in  the  individual. 


RACIAL  AND   INDIVIDUAL   DEVELOPMENT         361 

The  vocal  organs,  which  are  so  highly  developed  in  the 
throat  of  man,  and  the  nervous  structure  controlling  them, 
are  of  little  or  no  use  in  reacting  to  the  material  environ- 
ment, but  are  useful  chiefly  in  reacting  to  the  human  and 
mental  environment.  The  development  of  the  large  rep- 
resentative and  conceptual  centers  of  the  brain  is  also  the 
result  of  mental  rather  than  physical  needs. 

Since  the  conceptual  centers  acquire  control  over  the 
other  centers  and  through  them  of  the  whole  body,  and 
since  one's  occupation,  surroundings,  and  conduct  are 
determined  largely  by  one's  tastes  and  ideas,  it  follows 
that  the  physiological  development  of  man  may  be  greatly 
modified  by  his  conceptual  activity.  However  profound 
such  modifications  may  be  in  the  individual,  they  can  affect 
the  race  only  when  the  conditions  remain  the  same  for 
many  generations,  or  when  they  lead  to  sexual  selection 
favoring  the  development  of  the  characteristics  in  question. 

PSYCHICAL    AND   SOCIAL   EVOLUTION    IN    MAN 

Mental  evolution  is  affected  profoundly  by  that  portion 
of  the  physical  environment  which  is  significant  in  relation 
to  practical  needs.  In  civilized  life  this  physical  environ- 
ment is  entirely  different  from  that  of  more  primitive  modes 
of  existence.  The  surroundings  are  men  and  their  con- 
structions, while  nature  and  its  products  are  very  insig- 
nificant phases  of  the  environment.  We  now  have  little 
need  to  react  directly  to  nature's  forces  and  products,  but 
must  understand  and  operate  machines  made  by  man, 
to  utilize  and  transform  them.  The  child  has  to  adjust 
himself  to  a  man-made  environment  in  which  food  does 


362  GENETIC   PSYCHOLOGY 

not  grow  on  trees  or  run  in  the  forest,  but  must  be  obtained 
from  the  market  and  paid  for  by  means  of  little  round  pieces 
of  metal.  Clothing,  so  far  as  he  sees,  is  not  made  from 
vegetable  and  animal  fibers,  but  is  obtained  from  the  store. 
If  one  wishes  to  go  anywhere,  he  does  not  walk,  but  gets 
on  a  car  and  pays  money,  or  if  on  water,  in  a  boat,  and 
pays  money  also.  If  one  is  cold,  he  must  turn  something 
and  the  heat  will  come ;  if  one  wants  light,  he  turns  some- 
thing else;  if  he  wants  to  know  what  time  it  is,  he  does 
not  look  at  the  sun  or  the  stars  but  at  a  watch  or  a  clock. 
Mental  evolution  in  man  is,  therefore,  much  more  pro- 
foundly affected  by  the  artificial  and  social  environment 
than  it  is  by  the  natural. 

Not  only  is  the  modern  city  child  surrounded  by  men  and 
a  man-made  environment,  but  a  large  proportion  of  his 
reactions  are  to  men  rather  than  to  things.  He  also  has 
comparatively  little  contact  with  other  living  creatures 
than  man.  The  chief  stimuli  to  action  are  his  perceptions 
of  what  people  do  and  say.  In  such  of  these  actions  as 
express  emotions,  as  laughing,  crying,  etc.,  there  is  little 
difference  between  those  affecting  the  primitive  man  and 
the  child  of  to-day.  In  responsiveness  to  these,  therefore, 
the  child  resembles  the  primitive  man.  He  also  resembles 
him  in  being  affected  by  religious  and  other  mysterious 
ceremonies.  In  all  else,  there  is  little  in  what  the  man  of 
the  present  day  does  that  resembles  the  activities  of  the 
primitive  man,  and  hence  little  to  make  the  child  like  the 
primitive  man.  The  language  environment,  even  when 
it  persists  in  the  same  form  for  many  generations,  affects 
not  at  all  the  vocal  apparatus  of  the  race,  while  in  the 
development  of  the  individual  child  it  exercises  a  profound 
influence, 


RACIAL    AND    INDIVIDUAL    DEVELOPMENT         363 

If  the  difference  between  the  material  and  physical 
environment  of  the  child  and  that  in  which  the  primitive 
man  developed  is  great,  we  may  say  that  the  difference  in 
mental  environment  is  almost  infinitely  greater.  A  primi- 
tive people  with  little  or  no  language  other  than  that  of 
natural  signs,  with  no  means  of  measuring  or  keeping  ac- 
count of  time  or  distance  or  of  expressing  number  relations, 
has  a  mental  environment  so  small  that  it  would  hardly 
be  recognized  in  the  map  of  the  mental  influences  affect- 
ing the  people  of  a  civilized  country,  who  are  responding 
to  communications  from  the  other  side  of  the  globe  and 
guiding  their  actions  by  events  long  past,  or  those  antici- 
pated for  the  distant  future. 

All  the  actions  of  men  constitute  a  mental  environment, 
because  they  are  interpreted  in  subjective  terms,  as  ex- 
pressions of  feeling  and  purpose.  This  is  true,  to  only  a 
very  slight  extent,  of  animals,  flowers,  and  inorganic  things. 
We  may  say,  therefore,  that  the  human  environment  is  a 
mental  and  social  environment  in  a  greater  degree  than  it 
is  a  merely  physical  one.  With  the  advance  in  civilization, 
human  environment  becomes  more  and  more  influential 
in  the  reactions  of  the  individual,  because  added  to  the 
actions  of  living  men  are  the  traditions  and  records  of  what 
men  have  done.  The  conditions  of  life  are  also  such  that 
man  no  longer  struggles  directly  with  nature  for  his  live- 
lihood, but  by  some  form  of  specialized  activity  in  coopera- 
tion and  competition  with  other  human  beings,  he  indirectly 
obtains  the  means  of  subsistence.  There  are  few  occupa- 
tions in  our  present  complex  life  in  which  success  does 
not  depend,  to  a  greater  extent,  upon  one's  ability  to  react 
in  appropriate  ways  to  men  and  to  their  knowledge,  tastes, 


364  GENETIC   PSYCHOLOGY 

and  beliefs  than  it  docs  upon  one's  ability  to  deal  success- 
fully with  things.  The  successful  merchant  and  manu- 
facturer must  know  what  will  please  men  and  women  or  he 
fails,  whatever  his  practical  or  scientific  knowledge  of  things 
may  be.  While  this  is  true  in  a  marked  degree  even  in  the 
attainment  of  the  material  necessities  of  life,  it  is  true  in  a 
very  much  greater  degree  in  the  attainment  of  success 
in  immaterial  ways,  e.g.  in  obtaining  social  and  political 
positions. 

Every  development  of  social,  artistic,  moral,  religious, 
and  intellectual  interest,  and  every  new  mode  of  gratifying 
such  interest,  opens  out  a  new  line  of  development  for  the 
individual  and  the  race.  With  advance  in  civilization 
the  course  of  mental  development  is  determined  more  and 
more  by  these  human  influences  and  less  and  less  by  the 
material  environment  and  the  physiological  needs  of  the 
body.  There  is,  therefore,  a  psychical  development  largely 
independent  of  physiological  development  and  of  the  law 
of  natural  selection  in  the  form  of  physical  survival.  In- 
tellect in  both  the  child  and  the  race  is  developed  more 
rapidly  by  social  and  psychical  stimuli  than  by  the  stimulus 
of  things. 

In  the  associations  of  men  with  each  other,  especially 
in  the  cooperative  action  of  the  members  of  a  group,  some 
modes  of  reacting  to  the  mental  states  of  others  are  found 
effective,  and  because  of  their  satisfactory  results  are 
retained.  When  these  modes  of  reaction  are  established 
as  customs  or  laws  in  any  race  of  people  and  when  there 
are  institutions,  such  as  governments,  churches,  societies, 
and  corporations  to  give  expression  and  force  to  them, 
we  have  in  social  life  a  mental  environment  that  exercises 


RACIAL   AND   INDIVIDUAL    DEVELOPMENT         365 

a  profound  influence  upon  the  development  of  that  group 
of  people.  These  modes  of  behavior  and  these  institutions 
persist  for  many  generations,  modifying  profoundly  the 
development  of  each  generation  as  it  appears.  These 
social  customs  and  institutions  determine  from  without 
the  development  of  individuals  just  as  effectively  as 
structural  changes  in  lower  organisms  determine  their 
development  from  within. 

If  such  influences  lasted  long  enough,  the  nervous 
structure  of  the  race  as  well  as  of  the  individuals  of  each 
generation,  might  conceivably  be  modified  by  these  cus- 
toms and  institutions.  This  modification,  however,  if  oc- 
curring at  all,  would  be  chiefly  general  in  character,  increas- 
ing only  sensitiveness  to  human  influences  and  the  capacity 
for  aesthetic  and  moral  emotions  and  for  intellectual  acqui- 
sitions, without  producing  any  increase  in  any  particular  kind 
of  social,  artistic,  moral,  religious,  or  intellectual  tendency. 

The  principle  of  selection  acts  in  the  development  of 
customs  and  institutions  in  society  just  as  it  does  in  the 
individual  in  the  development  of  habits ;  those  found  most 
efficient  surviving,  as  a  rule;  although,  as  in  the  case  of 
habits,  the  most  economical  form  is  not  always  reached 
before  they  become  fixed,  and  having  become  fixed,  they 
may  persist  long  after  they  have  ceased  to  be  efficient. 
Social  organization,  like  consciousness,  develops  most  when 
changes  arc  taking  place.  The  more  distinctively  psychical 
peculiarities  of  a  people  are  therefore  preserved,  not  in 
their  brain  structure,  but  in  their  customs  and  institutions, 
knowledge,  and  beliefs,  which,  in  so  far  as  they  are  constant 
and  uniform,  cause  the  same  characteristics  to  develop  in 
most  of  the  individuals  of  each  generation. 


366  GENETIC   PSYCHOLOGY 

Changes  may  be  much  more  quickly  produced  in  the 
psychical  characteristics  of  a  people  than  in  the  instincts 
of  a  species  of  animals,  because  a  change  in  the  physio- 
logical structure  of  the  race  does  not  have  to  be  produced, 
but  only  a  change  in  the  environment.  Furthermore, 
the  change  of  psychical  environment  possible  to  man, 
through  his  power  of  imitation  and  ability  to  understand 
words,  enables  a  nation  to  acquire  in  a  very  short  time  many 
of  the  psychical  characteristics  of  another  nation.  The 
amount  of  change  in  mental  characteristics  that  may  be 
produced  in  a  people  by  such  control  of  the  social  and 
psychical  environment  as  man  now  possesses  is  far  greater 
than  could  be  achieved  through  any  conceivable  modifica- 
tion of  the  nervous  structure  of  the  race,  either  specific 
or  in  the  form  of  general  capacity.  The  future  progress 
of  the  human  race  will  therefore  be  more  and  more  through 
psychical  and  social  influences  embodied  in  customs,  in- 
stitutions, knowledge,  and  education. 

The  change  in  the  course  of  development  from  the  pro- 
duction of  specific  apparatus  to  the  production  of  capacity 
for  acquisition,  and  the  resulting  increase  in  importance 
of  the  environment  as  a  positive  factor  in  development, 
together  with  increase  in  the  part  that  consciousness  plays 
in  development,  has  tended  more  and  more  to  exalt  in 
importance  the  individual  rather  than  the  species.  In 
man,  who  is  not  only  conscious  but  self-conscious  and  aware 
of  what  he  has  been  and  what  he  may  become,  the  indi- 
vidual is  of  supreme  importance.  In  his  conscious  life 
is  found  a  distinct  world  separate  from  that  of  every  other 
individual  and  developing  from  a  very  simple  state  into 
higher  and  higher  types  of  unity.     To  trace  this  develop- 


RACIAL  AND   INDIVIDUAL  DEVELOPMENT         367 

ment  of  the  individual  consciousness  is  the  special  problem 
of  genetic  psychology.  In  order  to  do  this  we  must  know 
something  of  the  way  in  which  environment  affects  this 
inner  life  and  also  the  influence  U])on  the  development  of 
consciousness  of  the  physiological  and  sensory  motor  or- 
gans and  apparatus,  whose  activities  are  organized  before 
consciousness  has  begun  and  which  in  the  earlier  stages 
have  more  influence  upon  the  production  and  organization 
of  conscious  states  than  conscious  states  have  upon  them 
or  upon  the  working  of  the  representative  and  conceptual 
apparatus.  The  body  with  which  the  representative 
and  conceptual  apparatus  is  associated  determines  not 
only  the  type  of  organization  but  the  individual  temper- 
ament. The  actual  organization  and  development  of 
psychical  characteristics  take  place  as  the  individual  con- 
sciousness is  aroused  and  selects  for  survival  in  its  inner 
world  various  phases  of  the  environment.  Conscious 
selection,  therefore,  rather  than  natural  selection  is  the  chief 
factor  in  the  evolution  of  the  individual  consciousness. 

The  author  hopes  in  a  subsequent  volume  to  treat  of 
the  working  of  conscious  selection  in  the  development  of 
individual  consciousness  under  the  conditions  imposed  by 
the  material  and  psychical  environment  and  the  physio- 
logical and  sensory  motor  intelligence  with  which  we  have 
found  the  consciously  directed  intelligence  to  be  so  closely 
related. 

REFERENCES 

Baldwin,  J.  M.     Development  and  Evolution. 
Mental  Evolution,    Methods  and  Processes,  especially  Chap- 
ter VI. 


368  GENETIC   PSYCHOLOGY 

Baldwin,   J.   M.     Social    and    Ethical    Interpretation,  especially 

Chapters  II,  IV,  XIII. 
Chamberlain.    The  Child,  Chapter  VII. 

*  Conn,  H.  W.     Evolution  of  To-day. 
Method  of  Evolution. 

Darwin,  C.  R.     Descent  of  Man  and  Selection  in  Relation  to  Sex. 
Darwin,    Francis.      Habit    Illustrated    by    Morphology,  Science, 

September,  1908,  pp.  385-396. 
Davenport,  C.  B.     Experimental  Morphology. 
♦GuiLLET.      Recapitulation  and  Education,  Ped.  Sent.,  Vol.  VII, 

pp.  397-445- 
Haeckel.     Evolution  of  Man. 
Headley,  F.  W.     Life  and  Evolution. 
Kellogg,  V.  L.     Darwinism  of  To-day. 
McDougal.     Heredity  and  Environic  Forces,  Science,  Jan.  24, 1908. 

*  MiNOT,  C.  S.     The  Problem  of  Age,  Growth,  and  Death,  Pop.  Sci. 

Mo.,  Vol.  LXXI,  pp.  97-120,  193-215,  359-377,  455-473, 
509-523- 

Morgan,  T.  H.     Regeneration. 

Experimental  Zoology. 

♦Morgan,  C.  L.  Animal  Life  and  Intelligence,  Chapters  IV,  V, 
VI. 

Pearl,  Raymond.  Some  Results  of  a  Study  of  Variation  and  Cor- 
relation in  Brain  Weight,  Jr.  Comp.  Neu.  df  Psych.,  Vol.  XV, 
pp.  467-481. 

Reid.  Principles  of  Heredity,  Chapters  V,  IX,  X,  XI,  XII,  XIII, 
XIV,  XXI. 

Romanes,  G.  J.     An  Examination  of  Weismanism. 

*  Swift,  E.  J.     Mind  in  the  Making,  Chapter  VII. 
Tayler,  J.  L.     Aspects  of  Social  Evolution. 
Thomas.    Sex  and  Society,  pp.  223-314. 
Thomson,  J.  Arthur.     Heredity. 

Watkins,  G.  p.    Forms  of  Selection  with  Reference  to  Their  Applica- 
tion to  Man,  Pop.  Sci.  Mo.,  Vol.  LXXI,  pp.  69-83. 
Weismann,  a.    The  Germ  Plasm. 


INDEX 


Adaptive 

instincts,  100-103. 

activities,  257-285. 
Adenoids,  346. 
^Esthetic 

instinct,  104. 

feelings,  222. 

pleasure,  272,  354. 
Allen,  75. 

Amoeba,  39-43,  170,  286. 
Amphibia,  66-68. 
Anger 

as  an  emotion,  215. 
Angleworm,  220. 
Animals 

distinction  from  plants,  7,  8,  257. 

types  of  behavior  of,  39-88. 

domestic,  81-85. 
Ants,  72-76. 
Aphasia,  149. 

Arithmetic,  286-289,  322-325. 
Association,  243,  308. 
Attention 

mechanism  of,  162-168. 

of  animals,  250-254. 

Baldwin,  122. 
Basal  ganglia,  144. 
Beaver,  103. 
Bees,  267. 
Behavior 

as  a  common  characteristic,  2. 

as    basis    of    genetic    psychology, 

3.4- 
genesis  of,  8-13. 
structural  basis  of,  16-37. 
types  of,  39-88. 
distinguished     from     physiological 

processes,  87-88. 
of  species,  92-109. 
of  individuals,  111-139. 
structure  concerned  in,  141-168. 


Bell,  63. 

Bentley,  65,  128. 

Berry,  81,  121. 

Bethe,  63. 

Birds,    82,    102,    104,   107,    170,   204, 

247.  248,  331,  355- 
Bohn,  61,  62. 
Bose,  173. 
Bostick,  295. 
Brain 

of  vertebrates,  141-146. 

difference  of  man's,  146-152. 

functioning,  152-156. 

special  processes  of,  156-162. 

possibilities  of,  280. 


i,  352,  354- 
114,  118,  120,  250. 


Capacities, 
Cats,  81,  9^ 
Cattle,  97. 
Cell 

reproduction  and  germ,  331. 

in    individual   and   racial   develop- 
ment, 339-342. 

relations  in  development,  342-348. 
Cerebellum,  142,  144. 
Cerebrum,  141,  144. 
Chickens,  81,  115,  116,  120,  251. 
Child,   122,   124,   147,   181,  271,  292, 
293,  296,  298,  301,  303,  304,  310, 
317.  318,  319,  357.  361.  362. 
Children,  4,  117,  124,  184,  224,  286, 

301,  304,  305. 
Creek  chub,  65,  120. 
Clams,  60,  170. 
Cole,  84,  131,  240. 
Color 

sensations,  21,  22. 

perceptions  of  fish,  65. 

perceptions  of  insects,  73. 

perceptions,  199,  226. 

concepts,  304. 
Comparative  Psychology,  2. 


2B 


369 


37° 


INDEX 


Concepts 

physiological    mechanism    of,    162, 
'166-16S. 

and  reasoning,  247-248. 
Conceptual 

centers,  151,  152,  155,  166,  167,  361. 

intelligence,  275-281. 
Consciousness 

as  basis  of  genetic  psychology,  2-3. 

to   be   assumed   only   when   neces- 
sary, 13-14. 

of  amoeba,  42. 

and  learning,  127-128. 

objective  criteria  of,  169-178. 

subjective  criteria  of,  1 79-191. 

continuity  and  unity  of,  193-198. 

of  animals,  206-210. 

specific  states  of,  214-250. 
Cooperation 

of  animals,  97. 

of  men,  349,  350,  351,  363. 
Cord,  spinal,  143. 
Courtis,  24. 

Crabs,  62,  63,  113,  115,  176,  341. 
Crawfish,  63-64. 
Crow,  82,  103. 
Curiosity,  102. 

Darwin,  104,  194. 
Davis,  84,  131. 
Death  feint,  71. 
Deer,  237,  239,  339. 
Development 

stages  of,  12. 

of  motor  structures,  31-33. 

of  nervous  structure,  33-37. 

of  free  images,  126-139. 

of  concepts,  302-307. 

of  race  and  individual,  331-367. 
Dog,  37,   81,  98,  99,   108,    120,   121, 
^35,  136,  170.  186,  194,  195,  196, 
225,  238,  244,  252,  253,  254. 

Ears,  26. 
Echinoderms,  58. 
Elephant,  138. 
Embryo,  332,  333. 
Emotions,  215-217. 
Environment 

enlargement  of,  354-358. 


Evolution 

and  genesis  of  behavior,  8-13. 

physiological  of  man,  358-361. 

psychical  and  social,  361-367. 
Expressive  instinct,  106. 

Fear 

instinct  of,  93,  94. 

relation  to  religion,  107,  108. 

as  an  emotion,  215. 
Feeling 

in  animals,  214-217. 

pain,  217-222. 
Fi.sh,  64-66,  t20. 
Focalization,  208-210. 
Form 

perception  of,  22,  23. 

concept  of,  305. 
Foxes,  103. 
Franz,  145. 

Frog,    24,    36,    66-67,    141-143.    165, 
180,  192,  219. 

Genesis  of  behavior,  8-13. 

Germ  cell,  331,  332,  233- 

Goat,  268. 

Goltz,  143. 

Graber,  20. 

Gredler,  76. 

Grief,  215. 

Guinea  pigs,  76-78,  79. 

Habit 

of  starfish,  59,  60. 

formation,  111-119. 

complication    with    instincts,    119- 
126. 

and  memory,  244-245. 

and  reasoning,  247-248. 
Haggerty,  134. 
Hawk,  267. 
Hearing 

organs  of,  23-26. 
Hen,  96. 
Heredity,  12. 
Hobhouse,  133,  135 
Hodge,  III. 
Holmes,  68. 

Horse,  97,  215,  238,  292. 
Hydra,  53-56. 


INDEX 


371 


Ideas 

free,  126-139. 
Image 

free,  126-139. 

loss  of,  149. 

centers,  151. 

mental,  158-160. 

and  perceptions,  200-201. 

and  memories,  160-162,  238-247. 

in  learning,  299-302. 
Imitation,    loi,    123-126,    298,   310- 

Individual 

behavior,  111-139. 

and  racial  development,  331-368. 
Infant,  122,  136,  148. 
Infusoria,  43-53- 
Inhibition,  120. 
Instincts 

nature  and  differentiation,  76-93. 

individualistic,  93-95.  "" 

parental,  95-96. 

social,  97-99. 

adaptive,  100-102. 

play,  100. 

imitative,  loi. 

curiosity,  102. 

constructive,  102-103. 

aesthetic,  104. 

teasing,  105. 

jealousy,  105-106. 

e.xpressive,  100. 

regulative,  106-109. 

moral,  108. 

fear,  107. 

religious,  107-108. 

complication     with     habits,     119- 
126. 

specialization  of,  102-109. 
Intellectual 

states,  222-254. 
Intelligence 

objective  tests  of,  169-178. 

a  broader  conception  of,  257-259. 

physiological,  259-263. 

sensory  motor,  264-269. 

representative,  270-275. 

conceptual,  275-281. 

tj'pes  of  in  man,  281-284. 
Interest,  250-254. 


Jackson,  154. 
Japanese  mice,  21,  226. 
Jealousy,  105. 
Jelly-fish,  341. 
Jennings,  112,  116. 
Judd,  183,  236,  307. 

Keller,  24,  283. 
Kinnamcn,  85. 

Learning 

and  suggestive  stimuli,  28. 

and  habit,  116. 

and  consciousness,  183-184. 

nature  of,  287-288. 

physiological,  288-291.     . 

sensory  motor,  291-297. 

representative,  297-302. 

conceptual,  302-307. 

reversal  of  processes  of,  307-314. 

combination,  314-328. 

to  read,  317-321. 

to  write,  321-322. 

of  mathematics,  322-325. 
Light,  20-23. 
Lindley,  271. 
Littorina,  61. 

McDougall,  337. 

Manual  training,  312. 

Medulla,  142. 

Medusa,  56-58. 

Memory,  160-162,  238-247. 

Mental  images,  158-160. 

Minot,  189. 

Mobius,  120. 

Modifiability,  176-178. 

Molusca,  60-62. 

Monkey,   83-85,   133,   134,    137.    138. 

151,  170. 
Morgan,  115. 

Motion  and  intelligence,  172-174. 
Motor  structure,  31-33. 

Natural  selection,  9,  348,  354. 
Nervous  system 

of  man  and  animals,  146-152. 
Neuroses,  257. 
Nicoli,  198. 


372 


INDEX 


Objective 

terms,  4,  198-205. 
Optic  thalami,  141. 
Ontogenetic,  331. 
Organisms 

subject  of  study,  2-3. 

characteristics  of,  5-8. 
Organoses,  257. 

Pain,  217-222,  353,  354. 

Paplow,  198. 

Paramecium,  43-53,  113,  182. 

Parrots,  82. 

Penguin,  96. 

Perception 

physiology  of,  156-158. 

and  images,  158-160. 

of  space,  227-233. 

of  objects,  233-238. 
Phototropic,  20. 
Phylogenetic,  331. 
Physiological 

processes,  87-88. 

intelligence,  259-263. 

learning,  288-291. 
Pigeon,     36,     81,     82,     135,    176, 

232. 
Pigs,  235. 

Plants,  7,  8,  257,  264. 
Play,  100. 
Pleasure,  353. 
Preyer,  116. 
Prince,  204. 
Psychic  factor,  13-14. 
Psychoses,  257. 
Purpose  and  intelligence,  174-175. 

Raccoons,  83-85,  131. 

Racial  instincts,  95-96. 

Ranatra,  68-71. 

Ransom,  63. 

Rat,  78-81,  118,  177,  242. 

Reasoning,  247-250. 

Recognition,  245-246. 

Refle.xes,  92,  93. 

Religious  instinct,  107-108. 

Representative 

centers,  154,  155. 

intelligence,  270-275. 

learning,  297-302. 


Romanes,  225. 

Salmon,  95. 

Selection    in    individual    and    racial 

development,  348-354. 
Sensations,  222-227,  234. 
Sensitive 

structures,  17-26. 
Sensory  motor 

centers,  157. 

intelligence,  264-269 

learning,  291-297. 
Shark,  219. 
Sight 

organs  of,  20-23. 
Smell 

organs  of,  19. 

sense  of,  28-29,  222-225. 
Smith,  113. 
Social    instincts,    97-99,    124,    361- 

367- 
Somatic 

sense  organs,  30-31. 

motor  organs,  23- 
Sound  stimulation,  23-26. 
Space  perception,  227-233. 
Sparrows,  9. 
Spaulding,  62. 
Stentor,  50-53,  116,  341. 
Stimuli 

fundamental,  18. 

tactile,  18. 

chemical,  18-19. 

light,  20-23. 

sound,  23-26. 

suggestive,  26-30,  239-241. 
Stratton,  266. 
Structure 

as  a  common  characteristic,  2. 

as  determining  survival,  9-12. 

basis  of  behavior,  16-37. 

sensitive,  17-26. 

motor,  31-33. 

and  complex  behavior,  141-168. 

and  consciousness,  169-170. 
Subconsciousness,  204-205. 
Subjective,  198-205. 
Suggestive  stimuli,  26-30,  239-241. 
Survival,  9,  119. 
Sympathy,  216. 


INDEX 


373 


Taste 

organs,  18-19. 

sensations,  222-223. 
Teasing,  105. 
Tendon  reflex,  164. 
Thorndike,  83,  131. 
Thyroid,  345. 

Toilet-making  instinct,  103-104. 
Tortoise,  67-68. 
Touch 

organs,  17-18. 

sensations,  222-223. 
Triplett,  120. 
Turner,  75. 
Types 

of  intelligence,  257-284. 

of  learning,  286-328. 


Unity 

of  organism,  6-7. 

of  consciousness,  187,  193-198. 

Variation,  12,  328,  329. 
Vertebrates 

nervous  apparatus  of,  1 41-146. 
Visual  stimuli,  20-23. 
Volition,  250-254. 
Vorticella,  iii. 

Washburn,  65,  225. 
Wasps,  71-73,  232. 
Watson,  79,  242. 
Wolves,  98. 

Yerkes,  21,  24,  66. 


OF  THE 


A  LIST  OF  BOOKS  FOR  TEACHERS 

Published  by  The  Macmiltan  Company 


ARNOLD,  Fei.ix.  A  Text-Book  of  School  and  Class  Management. 
Theory  and  Practice.    Cloth,   izmo.   xxu  +  ./09  pages.   Index.    3 1-~5  "et. 

BAGLEY,  William  Chandler.  Classroom  Management :  Its  Principles 
and  Technique.  By  William  Chandler  Bagley,  Superintendent  of  the 
Training  Department,  State  Normal  School,  Oswego,  N.Y. 

Cloth.     i2mo.     xvU-\- 3^2  pages.     $1.2^  net. 

The  Educative  Process.         Cloth.    i2mo.    xix  -\-j^8 pages.    $1.25  net. 

BUTLER,  Nicholas  Murray.  The  Meaning  of  Education,  and  Other 
Essays  and  Addresses.  By  Nicholas  Murray  Butler,  President  of  Colum- 
bia University.  Cloth.     i2ino.     xii  T  2J0  pages.     $1.00  net. 

CHUBB,  Percival.  The  Teaching  of  English.  By  Percival  Chubb,  Princi- 
pal of  High  School  Department,  Ethical  Culture  School,  New  York. 

Cloth.     i2mo.     xvii-\-  411  pages.     $1.00  net. 

COLLAR,  George,  and  CROOK,  Charles  W.  School  Management  and 
Methods  of  Instruction.  By  George  Collar  and  Charles  W.  Crook, 
London.  Cloth,     izmo.     viii+  jj6  pages.     $1.00  net. 

CRONSON,  Bernard.  Methods  in  Elementary  School  Studies.  By 
Bernard  Cronson,  A.B.,  Ph.D.,  Principal  of  Public  School  No.  3,  Borough 
of  Manliattan,  City  of  New  York.         Cloth.    i2mo.    167 pages.    $1.2$  net. 

Pupil  Self -Government.  Cloth.    i2mo.    ix  -\- 107  pages.    $.gonct. 

CUBBERLEY.  Syllabus  of  Lectures  on  the  History  of  Education.  With 
Selected  Bibliographies  and  Suggested  Readmgs.  By  I'^lKvood  1'.  Cub- 
berley,  Associate  Professor  of  Education,  Iceland  Stanford  Junior  Univer- 
sity.   Second  Edition,  revised  and  enlarged.     In  two  parts. 

Part  I,v-\  I2g  pages,  $  i.^o  net ;  Part  II,  xv  -|-  j6i  pages,  $  i.^o  net. 

Complete  in  one  volume,  $  2.00  net. 

DE  GARMO,  Charles.  Interest  and  Education.  By  Charles  De  Garmo, 
Professor  of  the  Science  and  Art  of  Education  in  Cornell  University. 

Cloth.     i2mo.    xvii-\-  2J0 pages.     $1.00  net. 

The  Principles  of  Secondary  Education. 

I'ol.  I,  Studies.     Cloth.     i2mo.     xii -\- 2gg pages.     $1.2^  net. 

Vol.  II,  Processes  of  Instruction,     xii  +  200 pages.     $  i.oo  net. 

Vol.  Ill,  Processes  of  Instruction.     In  press. 

DEXTER,  Edwin  Grant.    A  History  of  Education  in  the  United  States. 

By  Edwin  Grant  De.xter,  Professor  of  Education  in  the  University  of  Illinois. 

Cloth,     xxi  +  665  pages.     Svo.     S  2.00  net. 

DUTTON,  Samuel  T.  Social  Phases  of  Education  in  the  School  and  the 
Home.  By  Samuel  T.  Dutton,  Superintendent  of  the  Horace  Mann 
Schools,  New  York.  Cloth.    i2mo.     ix -{■  2sg  pages.     $1.25  net 

DUTTON  &  5NEDDEN.     The  Administration  of  Public  Education  in  the 

United  States.     By  Samuel  Train  Dutton,  A.M.,  and  David  Snedden, 

Ph.D.     With  an  Introduction  by  Nicholas  Murray  Butler,    Ph.D.,  LL.D. 

Cloth,     viii  +  sgj  pages.     Bibliography.     Index.     i2mo.     $i.j$net. 


A  LIST  OF  BOOKS  FOR  TEACHERS  ~  Continued 


FITCH,  Sir  Joshua.  Educational  Aims  and  Methods.  Lectures  and  Ad- 
dresses by  Sir  Joshua  Fitch,  late  Her  Majesty's  Inspector  of  Training 
Colleges.  CloiA.     xii-\-  ^^8 pages.    i2mo.    $1.25  net. 

Lectures  on  Teaching.  Cloth.    xiU-\-jgj pages.    i6mo.     $1.00  net. 

OILMAN,  Mary  L.  Seat  Work  and  Industrial  Occupations.  A  Practical 
Course  for  Primary  Grades.  By  Mary  L.  Gilman,  Principal  of  the  Clay 
School,  Minneapolis,  Minn.,  and  Elizabeth  L.  Williams,  Principal  ot  the 
Holmes  School,  Minneapolis,  Minn. 

Fully  illustrated.     Cloth.     141  pages.     Square  i2mo.     $.^0  net. 

GANONG,  William  F.  The  Teaching  Botanist.  By  William  F.  Ganong, 
Ph.D.,  Smith  College.  Clot/i.     i2tno.     xi -\-  2jo  pages.     $1.10  net. 

GRAVES,  Frank  P.  A  History  of  Education  before  the  Middle  Ages.  By 
Frank  Pierrepont  Graves,  Ohio  State  University. 

Cloth.    J20  pages.    Bibliography.     $1.10  net. 

HALLECK,  Reuben  Post.  The  Education  of  the  Central  Nervous  System. 
A  Study  of  Foundations,  especially  of  Sensory  and  Motor  Training.  By 
Reuben  Post  Halleck,  M.A.  (Yale) . 

Cloth.    i2mo.     xii  -\-  2^8 pages.     $1.00  net. 

HANUS,  Paul  H.  A  Modern  School.  By  Paul  H.  Hanus,  Professor  of  the 
History  and  Art  of  Teaching  in  Harvard  University. 

Cloth.     i2mo.    X -\- J06 pages .     $1.2^  net. 

Educational  Aims  and  Educational  Values.    By  Paul  H.  Hanus. 

Cloth.     121/10.     vii-\-  221  pages.     $1.00  net. 

HERBART,  JOHN  FREDERICK.  Outlines  of  Educational  Doctrine.  By  John 
Frederick  Herbart.  Translated  by  Alex.  F.  Lange,  Associate  Professor  of 
English  and  Scandinavian  Philology  and  Dean  of  the  Faculty  of  the  College 
of  Letters,  University  of  California.  Annotated  by  Charles  De  Garmo, 
Professor  of  the  Science  and  Art  of  Education,  Cornell  University. 

Cloth.     Large  127710.     xi-\- jj^  pages.     $i.2§  net. 

HERRICK,  Cheesman  A.  The  Meaning  and  Practice  of  Commercial  Edu- 
cation. By  Cheesman  A.  Herrick,  Ph.D.,  Director  of  School  of  Com- 
merce, Philadelphia  Central  High  School. 

Cloth.     XV -{- 378 pages.     i2mo.     $1.2^  net. 

HORNE,  Herman  Harrell.  The  Philosophy  of  Education.  By  Herman 
Harrell  Home,  Assistant  Professor  of  Philosophy  and  Pedagogy  in  Dart- 
mouth College.  Cloth.     8vo.     xvii-\- 2g^  pages.     $1.50  net. 

The  Psychological  Principles  of  Education.    By  Herman  Harrell  Home. 

Cloth.     i27no.     xiii  -f-  4J5  pages.     $i.J5  net. 

HUEY,  Edmund  B.  The  Psychology  and  Pedagogy  of  Reading.  By  Pro- 
fessor Edmund  B.  Huey,  of  the  Western  University  of  Pennsylvania. 

Cloth.     i27no.     xvi-\-  46Q  pages.     $1.40  net 

KILPATRICK,  Van  Evrie.  Departmental  Teaching  in  Elementary 
Schools.     By  Van  Evrie  Kilpatrick. 

Cloth.     12)710.     xiii -\- Ijo pages .     167710.     $.60  net. 


A  LIST  OF  BOOKS  FOR  TEACHERS  -  Contmaed 


KIRKPATRICK,  Emvix  A.    Fundamentals  of  Child  Study.     By  Professor 

Edwin  A.  Kiikpatrick,  Principal  of  State  Normal  School,  Fitchburg,  Mass. 

ClofA.     i2mo.     xxi-]r  384  pages.     $1.25  net. 

MAJOR,  David  R.  First  Steps  in  Mental  Growth.  A  Series  of  Studies  in 
the  Psychology  of  Infancy.  By  David  R.  Major,  Professor  of  Education 
in  the  Ohio  State  University. 

Cloth.     xiv-\- 360 pages.     i2mo.     $1.2^  net. 

THE  McMURRY  SERIES  Each,  cloth,  I2mo. 

General  Method. 

The  Elements   of  General  Method.     By  Charles  A.  McMurry. 

J^J  pages.     $.gonet. 

The  Method  of  the  Recitation.     By  Charles  A.  McMurry  and  Frank  M. 

McMurry,  Professor  of  the  Theory  and  Practice  of  Teaching,  Teachers 
College,  Columbia  University.  xi -{-j2g  pages.     $.go  net. 

Special  Method.     By  Charles  A.  McMurry. 

Special  Method  in  Primary  Reading  and  Oral  Work  with  Stories. 

vii  +  loj  pages.     $.60  net. 

Special  Method  in  the  Reading  of  English  Classics. 

vi  +  2§ 4 pages.     $.^j  net. 

Special  Method  in  Language  in  the  Eight  Grades. 

vtii  +  ig2  pages.     $.yo  net. 

Course  of  Study  in  the  Eight  Grades. 

Vol.1.       Grades  I  to  IV.     vii -\- 2j6  pages.      $.f§  net. 
Vol.  II.     Grades  V  to  VIII.     v  +  22b  pages.     $.75  net. 

Special  Method  in  History.  vii  +  29/  pages.  $.-/^  net. 

Special  Method  in  Arithmetic.  vii  +  22;; pages.  $.jo  net. 

Special  Method  in  Geography.  xi-\-  21J  pages.  $.70  net. 

Special  Method  in  Elementary  Science.  ix-\-  2j§  pages.  $.js  net. 

Nature  Study  Lessons  for  Primary  Grades.     By  Mrs.  Lida  B.  McMurry, 

with  an  Introduction  by  Charles  A.  McMurry.      xi  -\-  jgi pages.     $.60  net. 


MONROE,  Paul.  A  Brief  Course  in  the  History  of  Education.  By  Paul 
Monroe,  Ph.D.,  Professor  in  the  History  of  Education,  Teachers  College, 
Columbia  University.  Cloth.     8vo.     xviii-\-  4og pages.     $1.2^  net. 

A  Text-book  in  the  History  of  Education. 

Cloth,    xxiii  +  zj-j  pages.     i2mo.    $/.go  net. 

A  Source  Book  of  the  History  of  Education.     For  the  Greek  and  Roman 

Period.  Cloth,    xtii-^  jrj pages.     8vo.     $2.25  net. 

O'SHEA,  M.  V.  Dynamic  Factors  in  Education.  By  M.  V.  O'Shea,  Pro- 
fessor of  the  Science  and  Art  of  Education,  University  of  Wisconsin. 

Cloth.     i2mo.     xiii  -{-J20  pages.     $1.25  n&U 

Linguistic  Development  and  Education. 

Cloth.     i2mo.     xvii  -\-j4J  pages.     $1.2^  net. 


A  LIST  OF  BOOICS  FOR  TEACHERS  —  Continued 


PARK,  Joseph  C.  Educational  Woodworking  for  Home  and  School.  By 
Joseph  C.  Park,  State  Normal  and  Training  School,  Oswego,  N.Y. 

Cloth.     i2mo.     xiii -\- jio  pages,  tllus.     $,1.00  net. 

PERRY,  Arthur  C.  The  Management  of  a  City  School.  By  Arthur  C. 
Perry,  Jr.,  Ph.D.,  Principal  of  Public  School  No.  85,  Brooklyn,  N.Y. 

Cloth.     i2mo.    via  +  j^o  pages .     $1.25  net. 

ROWE,  Stuart  H.  The  Physical  Nature  of  the  Child.  By  Dr.  Stuart  H. 
Rowe,  Professor  of  Psychology  and  the  History  of  Education,  Training 
School  for  Teachers,  Brooklyn,  N.Y. 

Cloth.     i2mo.     vi-\-  211  pages.     $.go  tiet. 

ROYCE,  JosiAH.  Outlines  of  Psychology.  An  Elementary  Treatise  with 
some  Practical  Applications.  By  Josiah  Royce,  Professor  of  the  History 
of  Philosophy  in  Harvard  University. 

Cloth.    i2mo.     xxvii-\-jg2 pages.     $1.00  net. 

SHAW,  Edward  R.    School  Hygiene.     By  the  late  Edward  R.  Shaw. 

Cloth.     vii-\-  2£§  pages.     j2tno.     $1.00  net. 

SHURTER,  Edwin  DuBois.  The  Rhetoric  of  Oratory.  By  the  Associate 
Professor  of  Public  Speaking  in  the  University  of  Texas. 

Cloth.    J2J  pages.     i2mo.    $1.10  net. 

SMITH,  David  E.  The  Teaching  of  Elementary  Mathematics.  By  David 
E.  Smith,  Professor  of  Mathematics,  Teachers  College,  Columbia  Uni- 
versity. Cloth.     XV  -\-  J12 pages.     121110.     $1.00  net. 

SNEDDEN  a.\d  ALLEN.  School  Reports  and  School  Efficiency.  By  David 
S.  Snedden,  Ph.D.,  and  William  H.  Allen,  Ph.D.  For  the  New  York 
Committee  on  Physical  Welfare  of  School  Children. 

Cloth.     i2mo.     xi  -\- i8j  pages.     $i.£onet. 

VANDEWALKER,  NiNA  C.  The  Kindergarten  in  American  Education. 
By  Nina  C.  Vandewalker,  Director  of  Kindergarten  Training  Department, 
Milwaukee  State  Normal  School. 

Cloth.     xiii-\- 274 pages.     Portr.,  index,  121110.     $1.2$  net. 

WARNER,  Francis.    The  Study  of  Children  and  Their  School  Training. 

By  Francis  Warner.  Cloth,     xix  +  264 pages.     121110.     $1.00  net. 

WINTERBURN  AND  BARR.     Methods  in  Teaching.     Being  the  Stockton 
Methods  in  Elementary  Schools.     By  Mrs.  Rosa  V.  Winterburn,  of  Los 
Angeles,  and  James  A.  Barr,  Superintendent  of  Schools  at  Stockton,  Cal. 
Cloth,     xii  -\-  j^^ pages.     i2ino.     $j.2§net. 


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